The countdown 'til training camp is on.

In two weeks, the Browns will be back in Berea for five weeks of practices, meetings and preparations for the 2021 season — one that's filled with hype following several key additions to the defense and little changes to an offense that thrived in 2020.

We're examining each position on the roster as Day 1 of camp nears and continuing with a position that has always had the biggest spotlight.

The Quarterbacks

Baker Mayfield

Case Keenum

Kyle Lauletta

What we know:Mayfield and head coach Kevin Stefanski proved last season their chemistry can win the Browns a lot of football games. One of the biggest storylines last offseason was whether Stefanski's playbook would go to plan and bring the best out of Mayfield's skillset, which thrives when the rest of the offense is clicking at an uptempo pace. The answer was a resounding "yes," and the result was the end of the NFL's longest playoff drought. The most encouraging part was how much Mayfield ascended in the second half of the season following the bye week, when Stefanski and offensive coordinator Alex Van Pelt took a hard look into Mayfield's tape and found ways to improve his game. All three of them attributed their study to one of the biggest reasons why Mayfield tossed 15 touchdowns and just two interceptions in the remaining 10 games, including two playoff games. The stretch was Mayfield's best as an NFL quarterback, and the Browns believe some more playbook retooling will push Mayfield to an even higher level. "I think Baker definitely became more comfortable in what we were doing, but I would tell you that I became more comfortable with his skillset, and going across the board," Stefanski said in March. "I was learning about our players and our coaches were learning about our players throughout that beginning portion of the season. I just think it was the natural evolution of us as an offense as we all learned about each other a little bit more."

What we don't know:Stefanski has stressed all offseason that the offense — and rest of the Browns — can't be complacent in their preparations for 2021. Yes, they reached the playoffs last season and checked one of their biggest seasonal goals, but Stefanski knows all 14 opponents on their schedule will spend time watching their tape to formulate a strong plan to stop them this season. Mayfield and the offense have to be ready for defenses to be better prepared for their play-action calls, run schemes and deep balls that helped them control games. That's no easy task, but we'll finally get to see in training camp and the early parts of the regular season just what Stefanski and Mayfield planned to ensure the offense continues to trend upward.

The X-Factor: It's Mayfield, and — more specifically — his in-game chemistry with Stefanski. The duo always seemed to be on the same page when it came to play calls and proper execution last season. That's what led to standout offensive performances in Week 4 against the Cowboys, Week 13 against the Titans and the incredible first-half performance in the Wild Card versus the Steelers. When the offense is playing at that level, the Browns are practically unbeatable.

The biggest number: 8. That's how many games Mayfield achieved a QBR over 80, according to ESPN’s Jake Trotter. The only two QBs with more 80+ QBR performances were Patrick Mahomes and Aaron Rodgers.

Says it all: "In a general sense, what I will tell you guys is we have to be more efficient on third and fourth downs. We have to be better early on early in the season. Obviously, we got better as the year went on, but for me, it is continuing to put us in manageable situations to win ball games and extend leads. Obviously, my priority is always winning. That is first and foremost and the biggest goal I will always have, and then personal stuff after that always comes with winning." - Mayfield

How many were kept on the initial 53-man roster last year?: 2