Lions training camp preview: Five breakout candidates to watch

Allen Park — The Detroit Lions open training camp next week.

Yesterday we took a look at the position battles we'll be watching, while today we turn our attention to five players with the potential to deliver breakout performances in 2019. 

Safety Tracy Walker

A third-round pick out of Louisiana–Lafayette in 2018, the Lions had the luxury of slowly bringing along Walker as a rookie. He saw action in all 16 games, but played fewer than 20 snaps 11 of the first 12 contests. 

The strategy of caging his responsibilities was effective as Walker thrived in his limited role, proving equally adept in coverage and supporting the run. Now, with iron man Glover Quin removed from the depth chart, Walker is primed for a much larger role on the defense.

Development isn't always linear, and adding significantly more responsibility on to a player's plate can lead to disappointing results, but Walker's combination of speed, length and athleticism are a promising combination for NFL success. 

Offensive lineman Frank Ragnow

Ragnow's rookie season was predictably inconsistent. There were games where he looked every bit the part of a first-round draft pick and other weeks where his still developing skill set was exposed by opposing defensive linemen. 

More: ESPN: Lions' offensive 'arsenal' ranks No. 18 in NFL behind 'promising' trio

It wasn't pretty, but the eye-opening experience of going head-to-head with All-Pro defensive tackle Aaron Donald provided Ragnow a taste of the best the game has to offer, providing him all the film he could need to show where he needs to improve to close the talent gap.

With an offseason dedicated to preparing for an NFL season, as opposed to training for the combine, Ragnow is primed to make steady improvements in year two. 

Running back Zach Zenner

Zenner has been around the block a few times now, posting largely pedestrian numbers after his impressive preseason performance as an undrafted rookie in 2015. He averaged just 3.5 yards per carry his first three seasons. He also suffered a pair of devastating injuries during that stretch, first broken ribs and a collapsed lung his rookie year, followed by a pair of fractured bones in his back last year. 

But he returned stronger than ever following the latter injury and played a key role in Detroit's offense down the stretch in 2018. The sample size is small — 55 carries over eight games — but his decisive, north-south running style played well behind the team's new blocking scheme, resulting in a stellar 4.8 yards per attempt. 

If Zenner can maintain that late-season momentum into this year, he could push newcomer C.J. Anderson for the top backup spot on the running back depth chart. 

Linebacker Jarrad Davis

There's no question Davis made significant strides in his second season. He cleaned up many of the coverage woes that plagued him as a rookie and showcased a previously untapped ability to rush the passer, recording six sacks and generating 27 total pressures as a blitzer. 

Where Davis' game continues to lag is his tackling. A naturally aggressive player, he still occasionally over-pursues on play fakes or takes a less-than-ideal angle to the ball carrier. In total, he missed 17 tackles last season, according to Pro Football Focus. 

More:Former Lions coach Caldwell stepping away from Dolphins role for health issues

In Davis' defense, coach Matt Patricia's scheme is complicated and puts an onus on the linebackers to solve problems on the fly. The young defender is a smart player, with an unmatched work ethic, so improvement is bound to come with the increased comfort level of having a year in the system under his belt. 

If Davis continues to deliver as a pass-rusher, makes additional improvements in coverage and cleans up some of his tackling issues, there's Pro Bowl potential in the 2017 first-round pick. 

Cornerback Teez Tabor

Things haven't gone as planned for Tabor to this point. His second season was an unquestioned disaster, as the young corner allowed a perfect passer rating against when targeted by opposing quarterbacks. 

But publicly, the Lions have continued to express faith in the former second-round pick out of Florida. And he'll have another shot to win a starting job this training camp. There was some promising playmaking on display during the early portion of the offseason program, but also too many plays allowed given Detroit's top two receivers weren't practicing during those sessions. 

It's often said the biggest developmental jump is between a player's first and second season, but Tabor came into the league younger than most prospects and it wouldn't be a total surprise to see things start to click in year three. If not, he probably won't see the fourth and final season of his rookie deal in Detroit. 

jdrogers@detroitnews.com

Twitter: @Justin_Rogers