San Francisco 49ers head coach Kyle Shanahan has said he believes Mike Evans' Achilles tendonitis is not going to be "a long-term thing" after he limped off the field and missed the second half of Monday night's win over the Washington Commanders.

The 49ers moved to 6-0 on the year on Monday night after defeating the Commanders 23-17, in a game which saw Washington head coach Dan Quinn face more questions about his clock management. With 1:10 left in the first half, Evans caught a 16-yard pass from Brock Purdy, diving to haul in the throw to convert a second-and-15.

However, after the play, Evans stayed down. He tried to stretch his right leg, with medical staff running over to help him up. The 49ers veteran limped off the field, slowly making his way to the locker room, and was then pictured grabbing his left Achilles in the tunnel.

Evans, who had three catches for 94 yards, missed the rest of the game. He entered the clash with the Commanders questionable with an Achilles injury and an ongoing rib issue.

He also did not practice all week but was active anyway after posting a season-high 113 receiving yards against the Seahawks a week prior.

Following the game, 49ers head coach Shanahan has admitted Evans is suffering from Achilles tendonitis. Shanahan added that while it flared up against the Commanders, he does not believe it will be a "long-term" problem.

"I mean it's something that he's had before, something that bothered him throughout the week, so when you have Achilles tendonitis like he does, it kind of is what it is," Shanahan told reporters.

He continued, "It flared up tonight, and I hope that he recovered throughout the week, but you don't think it's a long-term thing. Right now it's almost cost him this game, and ended up costing him two quarters.

"Hopefully he'll be able to play next week but if not, we'll have to have the rest of the group step up and hopefully get him healed up after the bye week."

Shanahan also revealed Evans told him he would be good to go against the Commanders despite the Achilles issue. "It was a pretty close call in terms of that he wasn't able to go all week, but just talking to Mike, just something he has dealt with in the past in his career and he felt confident to be good today," he added.

"That was the confidence he gave me, but we knew he might not be able to last."

With Evans potentially set to miss Sunday's clash with the Atlanta Falcons, it leaves the 49ers with Jordan Watkins, Brandin Cooks, Jacob Cowing and Malik Turner as their only healthy wide receivers, with Deebo Samuel also out injured.

Thankfully, however, the 49ers, at 6-0, have a commanding lead in the NFC West, with San Francisco set to be on a bye week following the game against the Falcons, which could afford Evans plenty of time to rest up.