The Eagles pulled out a tough win over the Bills on Sunday without offensive tackle Lane Johnson. It’s unclear whether they’ll have to be without Johnson for another tough game this week against the 49ers.

Johnson had an MRI on his injured groin and is considered day-to-day, according to Ian Rapoport of NFL Network. At this point, the Eagles aren’t sure if Johnson will be able to go against the 49ers.

Johnson, one of the Eagles’ best players, was a full participant in practice all week and was not on the injury report, but on Sunday he experienced groin pain and was held out of the game.

The Eagles would love to have Johnson back for the game against the 49ers, which is a rematch of last season’s NFC Championship Game and a matchup of the two teams widely regarded as the best in the NFC this year as well. Johnson will surely push to play, although the Eagles may decide that they won’t put him on the field until he’s 100 percent, so that he’ll be healthy at playoff time — when they may face the 49ers again.