On the roster: Matthew Stafford, Matt Cassel, Jake Rudock
Key losses: None
Making the cut: Matthew Stafford
On the bubble: Cassel, Rudock
Best competition: Who backs up Stafford?
Cassel and Rudock split second-team reps equally throughout the open OTA and minicamp practices. It appears the Lions are going to give each quarterback a fair chance at winning the backup job.
Cassel has 106 games and 81 starts under his belt, which makes him a true veteran option as a backup. He and head coach Matt Patricia also have familiarity with one another from their time together in New England.
Rudock has been in Detroit's system for two years, and knows Jim Bob Cooter's scheme well. He's a young, developing player that was promoted to the active roster from the practice squad in 2016, and earned the backup role last year in his second season.
Both are good athletes and capable backups.
The big question mark is whether the Lions would be willing to keep three quarterbacks on the initial 53-man roster. They've kept two the past couple seasons, and that seems likely to happen again in 2018.
Training camp and the preseason will decide who emerges as Stafford's backup.
View photos of the quarterbacks competing for roster spots entering training camp.
Twentyman's take: The backup competition will be an interesting one to watch in training camp. Lions general manager Bob Quinn said this offseason that his goal is to compete for division titles, playoff victories and Super Bowl rings. If the Lions believe they have the roster to compete for those in 2018, then is a veteran backup like Cassel the better option? Does his experience allow the Lions to stay competitive and win some games if he has to step in and play for any period of time? What happens if the competition is close between Cassel and Rudock? Do they go with experience or potential?
When it comes to Stafford, he's entering his 10th year, and that gives the Lions a seasoned veteran at the most important position.
Stafford ranked in the top six in every major statistical category last season despite the fact that Detroit had the league's worst rushing attack and he was sacked 47 times.
The Lions return their offensive coordinator and their four top receivers, which puts the passing attack ahead of the game at this point in the season. That part of the offense should hit the ground running once training camp starts, and could be be one of the key strengths to this team in 2018.
Quinn spent a lot of resources this offseason bolstering the run game and solidifying the offensive line. If Detroit can give Stafford more support in the run game and protect him a little better, this offense has the potential to be one of the most explosive in the NFL.
By the numbers:
4,000: By reaching 4,000 passing yards in 2017, Stafford joined Peyton Manning as the only quarterbacks in NFL history to throw for 4,000 yards in seven of their first nine years in the league.
47: Number of times Stafford was sacked in 2017, second most among all NFL quarterbacks.
39: Completions of 25-plus yards last season for Stafford, which ranked second behind only Tom Brady (40).
99.3: Stafford's passer rating in 2017, which established a new franchise record.
Quotable: "Stafford's phenomenal," Patricia said. "He works hard, tough, smart. And you know what's great is when you have quarterbacks like that, where you can go out, and look (Jake) Rudock and Matt Cassel are the same guys, and you're going out and you're having football conversations. You're not really having to always explain everything from a, 'Let me draw this up for you and show you what I'm talking about.' You can just have the conversations, 'Hey, if this guy's here,' or 'This leverage is played like this' or 'The DBs in this position' or 'The front looks like this' and just for them to visually have those conversations with you, that's what's great.
"Matthew's unbelievable. He loves this game, like he loves football, loves to practice, loves to prepare. He wants to know as much information as possible, not only scheme-wise, he wants to know it from players, as far as the guys around him, as far as the guys on the other side of the ball."