SANTA CLARA – The 49ers open their week of preparations to face the Detroit Lions with few assurances of who will be available to start at right guard.

Starter Mike Person sustained a foot strain that forced him out of action in the second quarter of the 49ers' opener on Sunday against the Minnesota Vikings. His backup, Joshua Garnett, was carted off the field in the third quarter with an injury coach Kyle Shanahan described as a dislocated toe.

Neither injury is considered a long-term injury, Shanahan said on Monday. But it is unknown whether either player will be available to face the Lions on Sunday at Levi’s Stadium.

Reserve offensive lineman Erik Magnuson is making progress after sustaining a hamstring injury during the preseason. He is scheduled to return to limited practice this week, but Shanahan said Magnuson has only an outside chance to be available for the game.

Rookie tackle Mike McGlinchey filled in at right guard on Sunday after the injuries to Person and Garnett.

“I was so impressed by McGlinchey,” Shanahan said. “By no means did he play perfect. It was neat to see how he reacted on the sideline. There was nothing about him that was scared to try it."

Person is also the team's backup center, so the 49ers must look at how to fill that role if Person is unable to play this week.

Veteran guard Matt Tobin, whom the 49ers signed last week, is another option to start this week. The 49ers have two offensive linemen on the practice said: Zack Golditch and Najee Toran.


Wide receiver Marquise Goodwin left Sunday’s game against the Vikings with a right quadriceps contusion. Shanahan said Goodwin is listed as day to day.

Linebacker Brock Coyle sustained a concussion on Sunday and is in the NFL’s return-to-play protocol.

The 49ers have yet to make a decision on filling the spot on their roster that opened with linebacker Dekoda Watson going on injured reserve. The 49ers will have some players in for workouts on Tuesday, Shanahan said. Former New Orleans linebacker Hau'oli Kikaha and former Indianapolis linebacker Erik Walden are among those who will work out, ESPN reported.