SANTA CLARA -- All-Pro 49ers defensive tackle Justin Smith underwent an MRI examination on Monday, but coach Jim Harbaugh said more will be known about Smith's availability in the coming days.
"It's really going to be how he is today, tomorrow and Wednesday before we know anything," Harbaugh said a day after the 49ers defeated the New England Patriots 41-34 in a wild game Sunday night in Foxboro, Mass.
Smith played fewer than half of the 49ers' defensive snaps after sustaining an undisclosed injury to his left arm. The 49ers reported it as an elbow injury. Team athletic trainer Jeff Ferguson wrapped Smith's left arm around the elbow, but Smith was unable to return to action.
When asked if it's feared that Smith sustained a long-term injury similar to Parys Haralson, who is out with a torn triceps, Harbaugh said, "No, it seems to be two different things."
Smith said Sunday night that he'd do everything in his power to return to the playing field as quickly as possible. In Smith's absence, the New England Patriots scored 28 consecutive points to tie the game before the NFC West-leading 49ers pulled out the victory to improve to 10-3-1 on the season.
Harbaugh said Smith's exit had an impact, but overall the 49ers did well in compensating for the loss of one of their leaders.
"I thought the guys stepped in and did some really good things," Harbaugh said "Ricky Jean (Francois) did a really nice and I thought our guys stepped up. Really, the chances we had to get off the field didn't come from that position. We made some errors elsewhere."
Jean Francois recorded a sack of Patriots quarterback Tom Brady on a third-and-15 play with approximately five minutes remaining to force a punt after the 49ers had taken a seven-point lead in the fourth quarter.
The 49ers return to action Sunday night at the Seattle Seahawks. The 49ers need to win only one of their final two games to win the division title. However, the 49ers hold a half-game lead over the Green Bay Packers for the No. 2 seed in the NFC playoffs. The two top seeds earn a first-round bye in the playoffs, as well as a home game in the divisional round of the playoffs.