SAN DIEGO -- After missing practice on Thursday because of a concussion, San Diego Chargers tight end Ladarius Green fully participated in practice on Friday and is listed as questionable for Sunday's contest against the Detroit Lions.

Green said he still has not been cleared for contact after participating in Friday's non-padded practice.

Green said he's going through the NFL's concussion protocol program, and is hopeful he can play this weekend.

"Everything went good today," Green said.

Green last suffered a concussion in December when former New England Patriots cornerback Brandon Browner delivered a blow that dislodged the ball from the Louisiana-Lafayette product on a pass from Philip Rivers across the middle of the field.

Green missed the following game against the Denver Broncos after the hit, and played a total of 11 offensive plays in the final two games of the season against the San Francisco 49ers and Kansas City Chiefs.

Green said this week's concussion suffered during Wednesday's practice wasn't as severe.

"In December I got knocked out," Green said. "But it wasn't that bad at all."

With Antonio Gates serving a four-game suspension after violating the league's policy on performance-enhancing drugs, Green is slated to start if healthy on Sunday. Green said he's not concerned with filling the sizable shoes left by Gates' departure.

"I always do what he tells me to do," Green said about Gates. "Just go out there and be myself, play my game and just be the best me I can be, and not try to fill his shoes at all."

Along with Green, the Chargers have David Johnson, Kyle Miller and John Phillips as available tight ends on the active roster.

Outside linebacker Jeremiah Attaochu (hamstring) and rookie cornerback Craig Mager (hamstring) were limited participants in practice on Friday and are questionable for Sunday.

Offensive lineman Johnnie Troutman (forearm) and outside linebacker Tourek Williams (foot) did not practice this week and are listed as out for Sunday.