Streaming your starting QB, TE, or D/ST isn't the goal in fantasy football. But, if you're weak at a position where you only have to start one player, picking up usable fantasy weeks from the waiver wire can be a beneficial process. In typical, start-one quarterback, tight end, and D/ST 12-team formats, most of your league mates won't -- and shouldn't -- carry a backup QB or D/ST. Positional scarcity leaves the waiver wire flush with plausible weekly starting options based on their matchup and expected game-flow.
Simply put, because quarterback and defensive matchups are easier to predict and their output varies less on a weekly basis, sharp fantasy owners have an edge in their leagues if they can stream their "onesie" positions (usually their defense) better than their opponent.
Quarterbacks
Floor and Ceiling: Marcus Mariota vs. New York Jets
Since the Titans Week 8 bye, Marcus Mariota has caught fire. In this span, Mariota has completed 78 percent of his passes, he has a 124.5 passer rating, 6:1 TD-to-INT ratio, he's averaging 9.6 YPA, and has added 22/98/1 on the ground. For more context, Mariota's 9.7 percent completion rate above expectation trails only Drew Brees, Kirk Cousins, and Russell Wilson over the last four weeks. Mariota left the Titans Week 11 bout against the Colts early (elbow), but he's finished as a top-eight fantasy passer in his three other games over the last month of action. Now, the Titans are in a prime bounce-back matchup against a Jets side that has allowed multiple passing scores in seven of their last eight games.
Floor and Ceiling: Dak Prescott vs. New Orleans Saints
It's safe to say Dak Prescott is thankful for Amari Cooper. Over the last month, Prescott and the Cowboys pass offense has sprung alive. Not only has Cooper's addition taken pressure off of Prescott, but the Cowboys entire receiver corps has been more efficient. Per Next Gen Stats, Prescott has thrown into a tight window just 14 percent of the time since Dallas traded for Cooper, the fifth-lowest rate in the NFL. In Weeks 1-8, Prescott threw into a tight window 24 percent of the time (highest rate). Now, the Saints did neutralize Andy Dalton and Carson Wentz in Week 10-11, but they coughed up over 350 yards and at least two scores to Kirk Cousins, Jared Goff, and Matt Ryan over their last five games.
Deep: Case Keenum vs. Cincinnati Bengals
Keenum has just two top-12 (QB1) scoring weeks in 11 starts this season, but we have to be on board with the usually low-ceiling signal-caller in Week 13 because the Bengals defense has completely fallen apart. Over their last six games, Cincinnati has allowed the following weekly fantasy performances: QB12 (Roethlisberger), QB1 (Mahomes), QB1 (Fitzpatrick/Winston), QB3 (Brees), QB13 (Lamar Jackson), and QB5 (Mayfield). In this span, the Bengals have allowed passing gains of 20 or more yards 13 percent of the time -- the third-worst clip in the league. Keenum is still a fringe play with zero teams on a bye, but he's the best streaming option of the week if Mariota and Prescott are already claimed.
Tight Ends
Ceiling: Jonnu Smith vs. New York Jets
Even though he's seen three or fewer targets in three of his last four games, Jonnu Smith keeps delivering. Much like Marcus Mariota, the second-year tight end has caught fire since the Titans Week 8 bye, turning his 15 targets into a monster 13/185/3 receiving line. While Smith's target count remains low, we have to keep him on the streaming radar in Week 13 against the Jets. Granted, New York hasn't faced many alpha tight ends, but they have gotten whacked by Eric Ebron (4/71/1) and Rob Gronkowski (3/56/1) this season.
Floor: Matt LaCosse vs. Cincinnati Bengals
With Jeff Heuerman (ribs, lung) on season-ending IR, the Broncos starting tight end job falls to Matt LaCosse's. Standing 6'6" tall, LaCosse is likely to take over Heuerman's moderately valuable red-zone and check-down role. In Weeks 9-12 without Demaryius Thomas, Heuerman saw 19 percent of Broncos' targets and turned his 19 total passing looks into 16/147/1. Over the full season, Heuerman led Denver in red-zone targets per game (1.1). LaCosse will make his first start in a plus draw, too, as Cincinnati is allowing the fifth-most YPG (68.4) and ninth-most PPR points per target (1.61) to the position.
Deep: Gerald Everett and Tyler Higbee vs. Detroit Lions
In three games without Cooper Kupp this season, Tyler Higbee (9 targets) and Gerald Everett (8 targets) have each been involved just enough to place them on the streaming radar. There's just one problem, though... these two are splitting opportunity. Again, in Kupp's three missed contests, Higbee has run 50 routes to Everett's 37 (per Next Gen Stats). While Higbee has seen more playing time, Everett (3 targets) has been more involved in the red-zone than Higbee (1 target) with Kupp out of the lineup. Unfortunately, there is no way to decipher the better play out of these two tight ends this week. Both have TE2 appeal against a Lions defense that is permitting the fourth-most PPR points per target to the position.
Defenses
Floor and Ceiling: Titans D/ST vs. New York Jets
It's a little disconcerting that three of the top streaming plays at each position come from the most unpredictable team in football. We must trust the process, though. The Jets have scored just 23 points with Josh McCown at the controls over their last two games, while the veteran backup has completed just 54 percent of his passes, absorbed five sacks, and put up a paltry 57.5 passer rating. Unsurprisingly, the Bills and Patriots defenses each posted top-eight fantasy results against the Jets. The Titans are (hopefully) next.
Floor and Ceiling: Colts D/ST vs. Jacksonville Jaguars
The losers of seven-straight, Jacksonville now has to face the white-hot Colts without three starting offensive lineman (C Brandon Linder, LT Cam Robinson, G Andrew Norwell), they have a new starting quarterback, and will be without finally-healthy Leonard Fournette (suspension). Need I say more?
Deep: Packers D/ST vs. Arizona Cardinals
Even without Mike McCoy holding the offense back, the Cards have struggled immensely over their last four games. While Byron Leftwich has done a little bit better job utilizing David Johnson's skill set, Arizona's attack is still flat. In Weeks 8-12, the Cardinals are still last in yards gained per drive (22.0), they're second-from-last in drives ending in a score (22.7 percent), and their offensive line has allowed the highest pressure rate (37 percent) in this span. That's a problem ahead of Week 13 against a Packers defense that has recorded a 9.0 percent sack rate this season (third-best).
-- Graham Barfield is the managing editor of fantasy football content at NFL.com. Follow him on Twitter @GrahamBarfield.