Fabian Brandy has opted to return to Manchester United after Gillingham made an offer to extend the striker's loan deal.
The youngster scored twice in nine games for the League One side after joining in November and the Gills were keen to extend his stay at Priestfield until the end of the season.
However, Gills boss Mark Stimson has admitted that the forward has since picked up an ankle injury, which has destroyed their hopes of bringing him back for now.
"Well, Fabian has returned to Manchester United because he has picked up an ankle injury," Stimson told skysports.com.
"We did want to extend it because he has done really well for us, but the injury has closed that avenue off at the moment.
"Man Utd were happy to let us have him until the end of the season, but the boy wanted to go back there and he has now done his ankle again.
"Once he has recovered then we would love to have him back here, but that will be down to him again because he felt it was better for him to go back there.
"We can offer him the chance of regular first-team football, but it is up to him whether he wants to come back."
Gillingham were dumped out of the FA Cup on Tuesday night by Accrington Stanley, with Stimson left frustrated by his side's performance.
He added: "We didn't perform well last night, but it looked like we might be heading for a replay, which would have been a good result for us, but it wasn't to be.
"Everyone is disappointed with the way we played and they have every right to be."