Oxford United midfielder Marcus Browne will be out of action for several months because of a hamstring injury.
The 25-year-old, signed from Middlesbrough in January 2022, limped off during the first half of the U's 3-1 win over Barnsley last Saturday.
"We are not going to see Marcus for a few months," head coach Liam Manning told BBC Radio Oxford.
"It's a real blow and I can't speak highly enough about how he has progressed and his professionalism."
He continued: "It's just really unfortunate for him, he got himself into a good sport and was contributing massively to the team - I am gutted for him and for us."
Browne started all four of Oxford's League One games so far this season.
And Manning said it is time for other players to step up from the bench to fill the gap.
He added: "We have depth and we have options. Marcus' injury is an unfortunate part of the industry, players will pick up injuries and miss periods of time, but it opens the door for other people.
"The situation highlights the importance of depth and the players states of mind because sometimes you might feel a million miles away from the team but one injury and that can all change."
Oxford, who are currently fourth in League One with nine points from four games, host Charlton at the Kassam Stadium on Saturday.