Jason

Fox

Fox missed each of the Lions’ first four games, and has been sidelined since early August. With starting left tackle Jeff Backus off to a slow start, Fox shouldn’t be hurting for snaps once he finally returns to game action.

“He is a guy we drafted and he’s flashed some really strong potential,” Schwartz said. “He just hasn’t stayed healthy. ... We feel like he’s a good offensive lineman. He fits a lot of things that we look for.” Long on upside -- and knee problems -- Fox has appeared in four games through two NFL seasons.

Fox has been battling a foot injury since early in training camp, though a knee injury suffered in Thursday’s practice ended his season. He’s had knee problems since coming out of college. This isn’t to the same knee that has so often troubled Fox, but he will need surgery. The 2010 fourth-rounder remains a raw but intriguing developmental project.

The Lions are calling it a precaution rather than a setback. It’s a concern, though, for a player who has experienced knee problems since coming out of college, including an injury that ended his season prematurely last November. He’s already been passed by rookie Riley Reiff in the coaching staff’s eyes.

Foot and knee injuries have limited Fox to four games in two seasons, and he sat out last week’s minicamp with knee soreness. “It’s not just ability, it’s availability,” Schwartz said. “He needs to put some time together where he’s injury-free, from an evaluation standpoint, and prove that he can stay healthy over the long term.” Fox will be the Lions’ fifth tackle if he keeps his roster spot.

If that’s the case, Hilliard has a huge edge after appearing in all 32 games the past two seasons and making five starts. A seventh-round pick last season, Culbreath missed his entire rookie year with a blood pressure issue before getting arrested for marijuana possession in January. A fourth-round pick in 2010, Fox has appeared in just four career games due to injury. He missed June’s minicamp with knee soreness. Culbreath still has practice squad eligibility.

The duo combined for only one appearance last season. Hilliard has five career starts to Fox’s zero. The Lions presumably want Fox to win the job after spending the offseason talking him up, but injuries have helped limit him to just five games since he was the No. 128 overall pick of the 2010 draft. The Lions recently hosted free agent Winston Justice for a visit, and could still add outside competition.

Fox, a 2010 fourth-rounder, has appeared in all of five career games, and he’s expected to compete with Corey Hilliard for the job. After the Lions experienced some of the best O-line continuity over the past few years, they’ll be employing three new starters up front at left and right tackle and right guard.

Both players split reps during OTAs and minicamp, and that will continue over the summer as the Lions look for one of the two to step into Gosder Cherilus’ old position. “We’ll keep them as equal as we can and let guys work with different groups,” offensive coordinator Scott Linehan said. Fox has been viewed as the favorite to win the job, but he has never started an NFL game.

Fox was a fourth-round pick in 2010, so he won’t be going anywhere. Fox is expected to compete with Corey Hilliard and possibly others for the starting right tackle job in Detroit. GM Martin Mayhew recently said the Lions think Fox has “starter-type talent level.”