What we learned from Week 4 of 2017 NFL preseason

Kansas City Chiefs quarterback Patrick Mahomes can already complete passes that few others in NFL history have ever pulled off. He's so talented that he can turn the normally sleepy final night of the preseason into a lot of fun.

Mahomes' one half of work against the Titans' backups had its share of hiccups, including two passes that were nearly intercepted. But it also had three breathtaking vertical throws -- all completions to Demarcus Robinson for a combined 127 yards -- that showed Mahomes' potential once he learns the little things about professional QB play from coach Andy Reid and teammate Alex Smith.

"Alex is the perfect person for me to learn from. ... We worked with how to see coverages and everything like that. It's just stuff that he had learned throughout his process that he's helping me out, cutting out the mistakes in mine," Mahomes told the Chiefs' local broadcast crew.

One throw in particular -- thrown over 45 yards while Mahomes was running to his right, just before getting walloped -- was reminiscent of Aaron Rodgers or Mike Vick sorcery. The performance capped an encouraging month for Mahomes and gave Chiefs fans something to remember if Smith goes through a dry spell during the regular season.

Here's what else we learned during Thursday's 15 preseason finales:

1. Mahomes was only one part of a strong month for this once-maligned rookie quarterback class. Cleveland's DeShone Kizerdidn't play Thursday because he already earned the starting job. Chicago's Mitchell Trubiskylooked terrific in the preseason, although he wasn't allowed to do much in his start against the Browns. Trubisky didn't throw a pass until the team's fourth drive and wound up completing 2 of 5 passes on the night.

Perhaps the most surprising rookie quarterback performance of the month was the explosive play of 49ers third-round pick C.J. Beathard. The 62-yard rushing touchdown from Beathard was likely a one-time phenomenon, but it appears he will win the backup job over veteran Matt Barkley. It wouldn't be surprising to see Beathard get a chance to start games late in the season, perhaps before Mahomes gets off the bench.

2. The night was filled with unsettled quarterback situations. The Ravenssurprisingly playedRyan Mallett for three drives, with him completing 3 of 8 passes for 19 yards and a touchdown after the defense forced a turnover inside the 10-yard line. It wouldn't be shocking if Mallett is the team's Week 1 starter with Joe Flacco ailing. It also wouldn't be shocking if Mallett was released before the season started.

In Seattle, the team isn't worried about starting quarterback Russell Wilson. But the backup situation is a major concern with Trevone Boykin looking lost for much of the preseason, throwing his fourth interception Thursday night. It's possible Austin Davis could win the job over Boykin, but I mentioned the Seahawks and Ravens together because of their connection to Colin Kaepernick.

The Seahawks were the only team to visit with Kaepernick and their need for a quarterback is more pronounced now than it was in May. The Ravens were the only team to have a coach publicly support Kaepernick after speaking to him on the phone. Their quarterback need also is more pronounced than ever. A deluge of transactions will be coming over the weekend and it's still possible Kaepernick lands a job then or after Week 1 when contracts are no longer guaranteed.

3. Colts owner Jim Irsay commented again on his uncertain quarterback situation, making some eyebrow-raising remarks after being asked about Andrew Luck's status.

"It's a great question," Irsay told the Colts' broadcast crew. "It's been said before by one of the greatest athletes and competitors who've played any sport, the quote was this: 'These games, all games, are played on a four-inch field between your ears.' That's where it's at. You have to be able to deal with this not only physically, but mentally. I have no idea, no doubt that Andrew Luck, the person that is, he's going to come out of this thing not just how he was but a better QB. When is the question. That timetable is more on the Football Gods and Andrew's gut feeling on how he's feeling."

Irsay's comments appear to indicate that Luck is struggling to push through some mental barriers as he recovers from shoulder surgery, which wouldn't be out of the ordinary. Luck needs to trust his shoulder is truly ready to let it rip before the team lets him practice fully. General manager Chris Ballard also indicated that Luck is expected to be taken off the physically unable to perform list by Saturday's deadline. If nothing else, that shows confidence Luck will be able to play within the first six weeks of the season.

4. Many observers have wondered why second-year pro Brandon Allen hasn't received a chance to jump into the starting quarterback competition in Jacksonville. On Thursday, he answered the question after being intercepted three times in the first half.

5. Jets running back Matt Forte, via the New York Daily News, told reporters that he was assured by general manager Mike Maccagnan he will not be traded.

6. There were some happy injury returns on Thursday night. Bills left tackle Cordy Glenn played, a sign he'll be fully ready to play Week 1. Saints center Max Unger suited up for the first time in the preseason. Titans receiver Eric Decker also returned from an ankle injury and coach Mike Mularkey indicated to the team's broadcast crew that rookie receiver Corey Davis will be ready for Week 1.

7. Bengals receiver John Rossleft Thursday's game with a knee injury after a preseason where he barely was on the field. Cincinnati also saw No. 3 quarterback Jeff Driskel injure his thumb.

8. A pair of Bears might have seen their time in Chicago end. Wide receiver Victor Cruz and linebacker Lamarr Houston each suffered knee injuries against the Browns. Cruz appeared unlikely to make the team even before the injury and Houston was on the roster bubble because of his big salary.

9. After an encouraging performance by rookie quarterback Nathan Peterman, Bills coach Sean McDermott was asked if Peterman's more suited to the team's offense than Tyrod Taylor.

"Listen, Tyrod's our starter," McDermott responded to reporters.

10. Jets second-year quarterback Christian Hackenberg played all but two series of the Jets game, creating more positive moments than his other three preseason games combined. Despite that, he still completed fewer than half of his passes (10 of 22) for under five yards-per-attempt. Too many third down passes were thrown way out of bounds. I'd expect Bryce Petty to be the Jets' backup if he's healthy for Week 1.

11. Let's give Bucs coach Dirk Koetter the final words about the preseason, when remarking about the team's 1-3 record:

"I don't think anyone gives two craps about that. ... There's been a lot of talk. A lot of talk. Talking time is done."