Tight end Delanie Walker missed another OTA session on Tuesday after tweaking a knee during an indoor practice last week. The former 49er underwent an MRI on Monday and was scheduled to see the results late Tuesday afternoon, but coach Mike Munchak said he doesn’t believe the injury is serious. “It’s just soreness,” Munchak said. “It’s probably from him having a long season and not having as much time off as the rest of them. But he’s fine.” Also sitting out: wide receiver Justin Hunter (hamstring), wide receiver Kenny Britt (knee), wide receiver Roberto Wallace (ankle), safety Markelle Martin (groin), safety Robert Johnson (foot), center Eugene Amano (knee) and guard Chris Spencer (calf). Britt and Hunter practiced on Monday. Munchak said Britt was held out Tuesday as a precaution and Hunter hamstring was slightly sore at the end of Monday’s practice.