Brandon Allen signed his Bengals' contract the other day while checking another box.

Allen, a journeyman back-up quarterback, admits, "I've pretty much done it all in this league," except what he's about to do. Back up a rookie quarterback.

Let's see. Drafted. (Sixth-round in 2016 by Jacksonville.) Waived. (By the Jags and Rams.) Claimed. (By the Rams and Broncos.) Cut and signed to the practice squad. (By the Rams.) No. 3 QB (Rams). Back-up QB (Broncos.) Winning starter (for the Broncos against the Browns.) Losing starter (for the Broncos against the Vikings and Bills.) Signed as a free agent. (By the Bengals.)

But this is, after all, a pandemic, so roles are evolving. Could he be adding another line to the resume reading "quarantined quarterback?"

"I think that's still kind of up in the air," Allen said this weekend after passing enough tests and physicals to get into the team hotel. "I'm not entirely sure of the plan or anything like that. However they use me is what I'm here for.

"I definitely hope to help Joe (Burrow) out any way he wants. As a backup, you're there to help the starter be the best quarterback he can be."

He's already in good stead with Bengaldom since the win in his NFL debut last November with two TD passes on an a 125 passer rating took out Cleveland. Allen is now the fourth quarterback in an intriguing room that already has Burrow, the draft's overall No. 1 pick, and two sophomore quarterbacks who were on the Bengals active roster all last year in fourth-rounder Ryan Finley and college free agent Jake Dolegala.

If there's a year they let you have four quarterbacks between a 55-man roster and 16-man practice squad, maybe this is it.

For months before and after the pandemic head coach Zac Taylor and offensive coordinator Brian Callahan insisted Burrow didn't need a veteran, but the Allen signing conjures up memories of the last time the Bengals started a training camp with a rookie quarterback that didn't have the benefit of spring practices.

Just as the 2011 camp was opening, the Bengals signed veteran Bruce Gradkowski to back up Andy Dalton despite the presence of two backups from the previous season. It was simple. Gradkowski knew the playbook offensive coordinator Jay Gruden was installing from his time in Tampa Bay.

And that's why Allen is here. Taylor was his quarterbacks coach during his stint with the Rams and knows he's of good-guy stock (his dad is the pro liaison at the University of Arkansas) with a toughness that allowed him to throw 64 touchdowns in 42 college games for the Razorbacks.

"Since (Taylor is) a former quarterback I think he does a very good job explaining to the quarterback what he wants to see out of the offense," Allen said. "He does a great job of kind of being in the mind of the quarterback and seeing what we see. I think that's the best thing he does. But he's also got a great personality where he can get a whole team to buy into his philosophy. "

Last season he didn't learn the Denver offense until after the first week of the season, when the Broncos claimed Allen to back up Joe Flacco after the Rams cut him. When Flacco was ruled out of the ninth week of the season, Allen was ready enough to lead the win over the Browns behind his razor efficiency that accounted for nearly 10 yards per his 20 attempts.

In Denver's 24-19 win over the Browns, Allen displayed his strengths. At 6-1, he doesn't have great sheer physical talent. But the Bengals' book says he has a quick release, sound fundamentals, an ability to avoid the rush and hang in the pocket with a good feel for the game.

Allen lost his next two starts before giving way to the future in Drew Lock and when the Broncos brought in Pat Shurmur to run the offense after the season, Allen no longer fit. Obviously the Bengals are a better fit for him because of the system and he thinks the talents are a fit for a Rams-style offense.

"The talent in the receiver room is extremely high," Allen said. "From what I've see and what research I've done shows there are a lot of good players on this team. It's just taking the right pieces to get going.

"(The offense) can be very explosive when done right. I think Zac is teaching it perfectly ... We've got a lot of talent around Joe. It comes down to fine-tuning some things but I think when this offense can get going it can be very explosive."