ORCHARD PARK, N.Y. — ​There is a changing of the guard behind Josh Allen.

In one of the most surprising moves by the Bills this offseason, the team signed Mitchell Trubisky to a one-year deal to be Allen's back-up.

It will be an unfamiliar role for Trubisky, who has started 50 of the 51 games he's played in the NFL since being drafted second overall by the Bears in 2017. Over those four seasons, he averaged 208 passing yards per game, throwing 64 total touchdowns to 37 interceptions with a completion percentage of 64%. Ultimately that was not enough for Chicago to exercise Trubisky's 5th year option and allowing him to walk in free agency.

Training camp and the preseason will be our first extended look at Trubisky to see if he will be an upgrade from Matt Barkley, who served as Allen's back-up for 2+ seasons, throwing for 788 yards, 3 touchdowns and 4 interceptions in 8 games over that span. 

Very early observations through OTAs and minicamp would indicate Trubisky is still acclimating to the Bills offense, but he did have plenty of positive moments. 

The real question at QB is whether or not the Bills decide to keep a 3rd QB behind Allen and Trubisky?

Jake Fromm held that role last season, the first time the Bills have kept 3 QBs on the initial 53-man roster since Sean McDermott and Brandon Beane came to town. Of course, Fromm had arguably the most unique rookie season we've ever seen, serving at the team's emergency COVID QB. He did not practice with the team all season, staying away from teammates as a precaution and only getting on-field work with a coach or handful of practice squad players. Fromm told me it is the first time in his football life he did not take snaps in 11-on-11 work. He returned to that during this spring's OTAs and minicamp after a year removed. How the 2020 5th round pick was able to develop under those circumstances as a rookie will be very much in the spotlight over the next month-plus.

Davis Webb is the other option to be the Bills third QB. Webb has been on the practice squad the past two seasons, but held a role far beyond his position title​. He's earned high praise from the coaching staff as well as Allen and other players. Could he finally do enough at QB to earn a spot on the active roster?

I'd say the Bills will likely go back to keeping just two QBs, with Allen and Trubisky the guys. That would leave Fromm and Webb battling to make the practice squad.