ALLEN PARK, Mich. (AP) Three times in the past five years, the Detroit Lions have drafted an offensive lineman in the first round.

Now it's time for that young group to show some real progress.

''One of the things you're going to notice is that we're bigger and stronger. It's going to be more competitive,'' coach Jim Caldwell said recently.

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''We have a couple spots we're going to be fairly young, but I think in the grand scheme of things if we can keep them all healthy, keep them battled and fighting, we're going to come out of there with a really big unit up front. I'm certainly convinced of that.''

With Calvin Johnson lost to retirement, the Lions still have their share of skilled offensive players in Matthew Stafford, Golden Tate and Ameer Abdullah.

The big question is whether Detroit can build on its encouraging finish in 2015 - or whether the offense will look as it did when the team lost seven of its first eight games.

A lot will depend on the offensive line.

The Lions have had to reshuffle their line quite a bit over the past few seasons, with Jeff Backus, Rob Sims and Dominic Raiola having moved on into retirement.

Detroit used valuable first-round draft picks on tackle Riley Reiff (2012), guard Laken Tomlinson (2015) and tackle Taylor Decker (2016) - and the Lions also took guard Larry Warford (2013) and center Travis Swanson (2014) in the third round.

Those five players all figure to play significant roles this season as Detroit tries to recover from its disappointing 2015. Stafford was sacked 44 times last season, bringing his total to 89 over the past two years. The Lions also averaged only 83.4 yards rushing per game, the worst mark in the NFL.

Both those stats were a bit of an indictment of the offensive line.

''We learned from the mistakes we made, and we've moved on,'' Warford said. ''We've got to focus on what we're doing now as a group.''

Reiff has started every game he's played for the past three years, and Tomlinson was a starter for most of last season. The Lions have high hopes for Decker - Caldwell said he could play either left or right tackle.

Reiff now seems like the veteran of the bunch, and Caldwell said he expects plenty of intensity from the 27-year-old tackle no matter which side of the line he's on.

''Riley is a warrior. Riley does not care about anything other than wanting to play his position and play it well and he doesn't care where he plays,'' Caldwell said.

''He's a talented guy that's tough and hard-nosed, the exact kind of guy that you're looking for to lead your group.''

Much of Detroit's resurgence toward the end of last season could be attributed to a schedule that eased up down the stretch, but the Lions hope that improvement was a sign of things to come.

In late October, Detroit fired its offensive coordinator and two line coaches. Tight ends coach Ron Prince took over the offensive line.

Now the offensive linemen have had a chance to work with Prince for a while and become comfortable with Jim Bob Cooter, who was promoted to offensive coordinator during last year's shakeup.

That familiarity - and the natural maturation process with top draft picks - could pay dividends at the line of scrimmage this season.

''With offensive line play - in all of football - there's two aspects, there's mental and physical,'' Warford said. ''When you start getting the plays down, it enables you to play faster.''

NOTES: The Lions removed S Don Carey from the active/non-football injury list, and they put WR Ryan Spadola on injured reserve because of a torn pectoralis. Spadola was waived/injured on Tuesday.

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