49ers undecided on who will start at QB in Week 18

The 49ers are undecided on the plan at QB in Week 18.

San Francisco head coach Kyle Shanahan shared good news on the health of 49ers starting quarterback Brock Purdy during a Tuesday conference call.

Purdy’s Tuesday MRI showed that he avoided any long-term concerns from the injury he sustained late on Monday night versus Detroit.

“I’m relieved, but I wasn’t too concerned. I mean, I wasn’t too worried about it just with the information we had last night. It was good to just hear the same thing today,” Shanahan said.

The 49ers are classifying it as a right elbow contusion with nerve inflammation, but Shanahan said San Francisco is not expecting Purdy to play in Week 18 at Arizona.

That means the 49ers will likely be trotting out either Joshua Dobbs or Brandon Allen under center. Shanahan said it’s unclear early in the week which quarterback will get the start for the 49ers.

“We’re just starting really putting this game to bed right now and trying to catch up with Arizona, so I’ll decide that later in the day,” Shanahan said.

After Purdy exited with his right elbow injury, Dobbs closed the 49ers’ final drive against the Lions and directed San Francisco for a touchdown. Dobbs completed 3-of-4 passes for 35 yards and then completed the scoring drive himself with a 7-yard touchdown scramble.

When Purdy was previously sidelined with a shoulder injury earlier this season, Allen got the start for the 49ers in Week 12 at the Green Bay Packers. The 49ers lost 38-10 as Allen completed 17-of-29 passes with a 3-yard touchdown pass to George Kittle against one interception.

Barring injuries during the week, the one option that Shanahan ruled out was rookie practice squad quarterback Tanner Mordecai.

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