Start 'Em & Sit 'Em is the ultimate look at the weekly NFL matchups and how they'll affect your fantasy team. Sleeper alert features a player who's under the radar and could produce good numbers. Owners beware features a player who's a regular fantasy starter but could fail to meet expectations based on the strength of his opponent. Obvious fantasy starters like Aaron Rodgers and Adrian Peterson are not featured. For your final lineup decisions, check our weekly lineup rankings.
Start of the week
**Chris Johnson at Colts:** Sometimes in life, we need validation. So if you survived Johnson's poor performance last week, don't be afraid to start him in the fantasy semifinals. In fact, I see him as a must-start against a Colts defense that's allowed the third-most fantasy points to runners in 2011.
Quarterbacks - start 'em
Matthew Stafford at Raiders: Stafford had a nice stat line against the Vikings, and an upcoming matchup against the Raiders makes him a terrific option once again. Oakland's defense has given up 25 total touchdowns and the sixth-most fantasy points to quarterbacks, so look for Stafford to produce.
Tony Romo at Buccaneers (Sat.): The Cowboys might be choking before our very eyes (again), but Romo is still a tremendous option. He put up his best stat line of the season in a loss to the Giants, and facing a Buccaneers unit that ranks 27th against the pass is clearly a favorable matchup.
Tim Tebow vs. Patriots: It's Tebow time in Denver! The versatile quarterback has a great upcoming matchup against the Patriots, who have allowed the third-most fantasy points to quarterbacks this season. So while Tom Brady will be the best signal-caller in the game, Tebow should post a stellar stat line as well.
Carson Palmer vs. Lions: Palmer's interception issues are a concern, but he's still worth a look against a Lions defense that's allowed an average of 24.90 fantasy points to quarterbacks in their last four games. That includes 28.16 points to the combination of Christian Ponder and Joe Webb last week.
Matt Moore at Bills: Moore is expected to be under center this week to face the Bills, who have allowed 18 or more fantasy points to four of their last five opposing quarterbacks. That includes an 18.60-point stat line from Moore back in Week 11. So if you need a signal-caller, he's worth a look in fantasy's semifinals.
Sleeper alert - Rex Grossman at Giants: Grossman has scored 14 or more fantasy points in three of his last four games, and this week's matchup against the Giants is a favorable one. New York has allowed 26 total touchdowns and the second-most fantasy points to quarterbacks in 2011.
Quarterbacks - sit 'em
Philip Rivers vs. Ravens: Rivers has been on fire, scoring 43.46 fantasy points in his last two starts. And while I'm not telling you he's a must-sit this weekend, you should be aware that no team has allowed fewer fantasy points to opposing signal-callers than the Ravens. Temper your expectations.
Mark Sanchez at Eagles: Sanchez has flip-flopped good and bad fantasy totals in each of his last seven games, and last week he scored 25.64 points. Whether the trend continues remains to be seen, but facing a motivated Eagles defense on the road is not what I would call an attractive scenario.
Josh Freeman vs. Cowboys (Sat.): A disappointment in fantasy land, Freeman has scored double-digit points once in his last four games. And while the Cowboys haven't been great against the pass, their defense has allowed an average of fewer than 15 fantasy points per game to quarterbacks.
Ryan Fitzpatrick vs. Dolphins: The Amish rifle hasn't had much gunpowder lately, scoring 15 or more fantasy points once since Week 3. That includes a 5.96-point disaster against this week's opponent, the Dolphins, in Week 11. With a fantasy title berth on the line, Fitzpatrick is hard to trust.
Alex Smith vs. Steelers (Mon.): Unless you're hurting in a league that starts two quarterbacks, there's no reason to start Smith on Monday night. He's been too inconsistent to utilize during the fantasy postseason, and the Steelers have given up the third-fewest fantasy points to quarterbacks.
Running backs - start 'em
Reggie Bush at Bills: One of the better fantasy draft bargains, Bush has ascended to 18th in fantasy points among backs and should continue to find success this week against the Bills. Their defense has allowed an average of 21.84 fantasy points to running backs -- that's fourth-most in the NFL.
Shonn Greene at Eagles: Greene has been on absolute fire over the last two weeks, scoring 54.10 fantasy points in wins over the Redskins and Chiefs. Next on the schedule is a date with the Eagles, who rank 18th in run defense and have surrendered the seventh-most fantasy points to runners.
Sleeper alert - Felix Jones at Buccaneers (Sat.): Jones has been thrust back into a prominent role in the absence of DeMarco Murray, who is out for the season with a broken ankle. And with a matchup against the Buccaneers porous run defense up next, Jones should post a solid stat line.
Running backs - sit 'em
Rashard Mendenhall at 49ers (Mon.): One of the rules of the 2011 fantasy football season is that you never, ever start a running back against the 49ers if at all possible. Their defense hasn't allowed a touchdown to a back all season, so Mendenhall's prospects for posting great fantasy totals aren't good.
Ryan Mathews vs. Ravens: It's tough to bench Mathews, who has been on fire over the last three weeks. But if you have depth at the position, it makes sense to at least consider the move against the Ravens -- their defense is second against the run and has allowed a mere six rushing scores.
C.J. Spiller vs. Dolphins: The lead back in Buffalo in the absence of Fred Jackson, Spiller has earned flex-starter value. However, he's still a major risk against an underrated Dolphins defense that has given up just four rushing touchdowns and the fourth-fewest fantasy points to running backs.
DeAngelo Williams at Texans: Williams had a solid 15.10 fantasy points last week, but most of his production came on one run. In fact, 41.2 percent of his overall fantasy numbers this season have come on just four carries. Four! I'd bench him against the Texans, who rank fourth in the league against the run.
Peyton Hillis at Cardinals: This looks like a very good matchup on paper, but I'm not about to trust Hillis when it seems like even his head coach has reservations about his effectiveness. Hillis, who sat for most of the second half last week, hasn't scored double-digit fantasy points since Week 2, either.
Wide receivers - start 'em
Jordy Nelson at Chiefs: The decision to start Nelson is more about production and targets than it is about the matchup. With Greg Jennings out, Aaron Rodgers will be looking for Nelson more often in one of the league's most prolific pass attacks. He needs to be active across the board.
A.J. Green at Rams: Green is having one of the best rookie seasons at the wide receiver position, and this week's matchup against the Rams makes him a must-start in all leagues. St. Louis has given up 17 touchdown catches and the fifth-most fantasy points to wideouts, so look for Green to shine.
Marques Colston at Vikings: Trying to predict which Saints wideout will have the best fantasy week is impossible, but Colston remains a solid option based on a favorable matchup against the Vikings. Their defense has allowed 17 scores and an average of 25.12 fantasy points per game to wideouts.
Santana Moss at Giants: Moss posted a nice total against the Patriots last week, and his upcoming matchup against the Giants makes him worth a look in New York. The Giants have given up the second-most fantasy points (and just 4.26 fewer per game than New England) to wide receivers.
Nate Washington at Colts: While he hasn't replaced the production of injured teammate Kenny Britt, Washington has been a viable No. 3 fantasy wideout for most of the season. He should remain in that role against the Colts, who he burned for a pair of touchdowns and 15.70 fantasy points in Week 8.
Sleeper alert - Demaryius Thomas vs. Patriots: A talented wideout from Georgia Tech, Thomas has scored 30.70 fantasy points in the last two weeks as Tebow's top option. He's more than a nice No. 3 option against the Patriots, who have allowed more fantasy points to wideouts than any team.
Wide receivers - sit 'em
DeSean Jackson vs. Jets: Jackson did score a touchdown last week, but he posted a mediocre four catches against the Dolphins and has averaged just 5.74 fantasy points in his last seven games. With a date against a tough Jets defense next, I'd be concerned about Jackson's level of production.
Anquan Boldin at Chargers: How's this for a stat: Boldin hasn't scored double-digit fantasy points in standard leagues since Week 8! What's more, he's found the end zone once in that time. The Chargers have also allowed the seventh-fewest fantasy points to wideouts, so Boldin is a risky option.
Santonio Holmes at Eagles: While he did score a touchdown against the Chiefs, Holmes also had 12 yards and scored just 7.20 fantasy points. The Eagles have allowed an average of 13.35 fantasy points to wideouts in their last two games, and facing CB Nnamdi Asomugha is not exactly attractive.
Michael Crabtree vs. Steelers (Mon.): Crabtree has been a PPR asset, catching a combined 24 passes in this last four games. Unfortunately, this week's game against the Steelers and CB Ike Taylor is anything but favorable -- their defense has allowed the second-fewest fantasy points to wideouts.
Pierre Garcon vs. Titans: Garcon might be in the top 20 in fantasy points at his position, but he's been too inconsistent to trust in the postseason. What's more, he scored a meager 6.6 fantasy points in his last game against the Titans. Unless you're in dire need, keep Garcon on the sidelines.
**Owners beware - Vincent Jackson vs. Ravens:** Most fantasy owners don't have enough depth to sit Jackson, who ranks ninth in fantasy points at his position on NFL.com. However, he could be in for a tough weekend against the Ravens -- their defense has allowed a mere seven touchdowns to wideouts.
Tight ends - start 'em
Jermichael Finley at Chiefs: If Finley's goose egg last week didn't end your fantasy season, you should keep him active during the semifinals against the Chiefs. Not only will he see more targets with Jennings out, but Kansas City is tied for the third-most touchdowns allowed to opposing tight ends.
Owen Daniels vs. Panthers: Daniels had his first solid stat line in several weeks against the Bengals, posting seven catches and 10.00 fantasy points as one of T.J. Yates' favorite targets. The Panthers have allowed an average of close to eight fantasy points to tight ends, so keep Daniels active.
Sleeper alert - Anthony Fasano at Bills: Desperate for a tight end this week? Consider Fasano, who has a great matchup against the Bills. Their defense has surrendered eight touchdowns (tied for the most in the NFL) and the fifth-most fantasy points to opposing tight ends. Fasano is available in most leagues.
Tight ends - sit 'em
Greg Olsen at Texans: It's tempting to start Olsen after he scored an impressive 11.30 fantasy points in last week's loss to the Falcons, but an upcoming matchup against the Texans is anything but attractive. Their defense has allowed a mere two touchdowns and the third-fewest fantasy points to tight ends in 2011.
Dustin Keller at Eagles: Outside of his 18.10-point outburst against the Bills, Keller hasn't scored more than eight fantasy points in a game since Week 3. That lack of consistent production makes him a huge risk against the Eagles, who have surrendered the 10th-fewest fantasy points to opposing tight ends.
Jermaine Gresham at Rams: If you're thinking Gresham could be a sleeper this week, you might want to think again. Despite their overall struggles on defense, the Rams have been able to keep tight ends in check for most of the season. In fact, no team has allowed fewest fantasy points to the position.
Davis has a big name, but his production has been anything but huge this season. In fact, he's not even in the top 10 at his position based on fantasy points. He's a risk against the Steelers, who have been tough on tight ends this season.
Kickers - start 'em
Sebastian Janikowski vs. Lions: "Sea Bass" hasn't been as reliable in fantasy land this season as he was in 2010, but he's still a top-10 option. Owners should definitely keep Janikowski active against the Lions, who have surrendered an average of close to nine points per game to kickers.
Stephen Gostkowski at Broncos: Brady and Tebow are the headline names in this AFC battle, but Gostkowski could also be a factor when it comes to getting into your league's championship. Denver has allowed the fourth-most fantasy points to kickers, so Gostkowski is clearly a terrific option.
Sleeper alert - Phil Dawson at Cardinals: If you're looking for a potential one-week starter, consider adding Dawson off the waiver wire. The veteran out of Texas faces a Cardinals defense that has given up the third-most fantasy points to his position, so the matchup is definitely a favorable one for owners.
Kickers - sit 'em
Nick Folk at Eagles: Folk was a useful option for fantasy owners earlier in the season, but he's been far less productive in recent weeks. In fact, he's scored double-digits in one of his last five games. With a matchup against the Eagles next, Folk isn't someone who's fortunes are going to be reversed.
Shaun Suisham at 49ers (Mon.): Suisham has been a viable fantasy option against teams that have allowed a ton of points to kickers, but that's not the case against the 49ers. Aside from the Steelers, no team has allowed fewer fantasy points to opposing kickers. As a result, Suisham should be benched.
Matt Prater vs. Patriots:Fantasy owners might see Prater's 11-point performance last week and see him as a potential starter. And while he has been on a hot streak, Prater has a very bad matchup against the Patriots up next. Their defense has allowed an average of 6.46 fantasy points to kickers.
Defenses - start 'em
Lions defense at Raiders: The Lions put up a monster fantasy stat line last week, and DT Ndamukong Suh will now be back after a suspension. That makes this unit a top option against the Raiders -- defenses have scored a combined 29 fantasy points against them over the last two weeks.
Bengals defense at Rams: Defenses facing Sam Bradford and the Rams have averaged the most fantasy points at the position this season (including a combined 33 points over the last two games), so the Bengals are clearly a solid option for fantasy owners in the semifinals. Pick them up if available.
Cardinals defense vs. Browns: The Cardinals defense, which is available in most NFL.com leagues, has a ton of appeal this week against the Browns. Over the last two weeks, defenses facing Colt McCoy and Cleveland have scored a combined 29 fantasy points. Grab them now if you need a one-week option.
Sleeper alert - Titans defense at Colts: The Colts have been a nightmare on offense without Peyton Manning this season. In turn, this has been a unit to target in terms of defensive matchups. Enter the Titans, who put up a solid 16 fantasy points against Indianapolis in their last meeting of the year.
Defenses - sit 'em
Steelers defense at 49ers: A relative disappointment among fantasy defenses this season, the Steelers rank a mediocre 14th in points at the position on NFL.com as we enter the semifinals. Next this unit goes up against the 49ers -- defenses have averaged the sixth-fewest fantasy points against them.
Owners beware - Jets defense at Eagles: It's tough to bench the defense like the Jets, but the Eagles have Michael Vick back in the mix and will be more formidable on offense. What's more, just one defensive unit has scored double-digit fantasy points against Philadelphia over their last four games.
Michael Fabiano is an award-winning fantasy football analyst on NFL.com. Have a burning question on anything fantasy related? Tweet it to **@Michael_Fabiano** or send a question via **Facebook**!