49ers' Trey Lance taking first-team reps; Jimmy Garoppolo (thumb) could play at Rams

The San Francisco 49ers know, for sure, they will qualify for the upcoming postseason tournament if they earn a win at a 12-4 Los Angeles Rams side that cannot mathematically catch the Green Bay Packers for the conference's No. 1 seed this Sunday. 

What's unclear, however, is who will be atop the San Francisco depth chart at quarterback. 

49ers QB1 Jimmy Garoppolo missed this past Sunday's victory over the Houston Texans due to the reported Grade 3 sprain of the ulnar collateral ligament in his right thumb and chipped bone he first suffered on Dec. 23, and Matt Maiocco of NBC Sports Bay Area reports 49ers coach Kyle Shanahan said Wednesday Garoppolo is beginning midweek practice sessions as a limited participant. 

Rookie Trey Lance, who got the nod versus Houston, is taking at least a majority of first-team reps as of Wednesday. However, Shanahan added Garoppolo will start against the Rams if he's "near 100%" come this weekend, and also that he won't announce his starter before kickoff of Sunday's contest. 

Lance completed 16-of-23 passes for 249 yards with two touchdowns, one interception and a 116.0 passer rating to go with 31 rushing yards on eight carries in Week 17. 

One thing Shanahan must consider is that his 49ers can back into the playoffs regardless of what happens in their game if the 8-8 New Orleans Saints fall to the 7-9 Atlanta Falcons.