Kearse was reinstated this week from a three-game suspension for violating the NFL's policy on substances of abuse. He was arrested last October as a member of the Minnesota Vikings and charged with driving while impaired and possession of a firearm.
The Lions signed Kearse this offseason to play as a big safety on run downs and fill a special teams role.
Defensive coordinator Cory Undlin said Tuesday he was "very excited" to get Kearse back in the fold.
"He’s been working hard to get back while he’s been out," Undlin said. "Unfortunate situation, is what it is, but I think we’re all excited for him to be back, energy and everything that he brings."
The Lions' top three safeties, Duron Harmon, Tracy Walker and Will Harris, have all played more than 50% of the team's defensive snaps so far this season.
Kearse is unlikely to see that much work, and Undlin hinted that it might take time for his role to develop on defense.
"He hasn’t been out there," Undlin said. "You guys know it’s different working out on the side, doing whatever he’s doing to get ready, and then going out and actually playing in the game. So we’ll take it day by day, we’ll get him back in there and ease him in and we’ll see where he fits at the end of the week. But we’re excited to have him back."
Running back Bo Scarbrough also is eligible to come off injured reserve this week.
Cornerback Darryl Roberts (hip) was a new addition to the Lions' injury report Thursday, practicing on a limited basis because of a hip injury. He's been the Lions' primary nickel cornerback with Justin Coleman on injured reserve the last two weeks.
Tight end Hunter Bryant (hamstring), cornerback Desmond Trufant (hamstring), defensive tackle Da'Shawn Hand (chest) remained limited in practice Thursday, while special teams ace C.J. Moore missed his second straight practice with a calf strain.
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This article originally appeared on Detroit Free Press: Detroit Lions activate S Jayron Kearse, waive RB Ty Johnson