Transfer update from Doncaster Rovers boss Darren Ferguson

But the Scot has confirmed that he still hopes to sign a speedy striker before the loan window shuts on August 31.

The extent of Mason’s knee injury is likely to become clearer when Ferguson speaks to the media today ahead of Saturday’s trip to newly-promoted Cheltenham Town.

He joins fellow defenders Mathieu Baudry, Craig Alcock and Luke McCullough on the sidelines.

Tyler Garratt also took a knock to the ankle during Tuesday night’s win against Cambridge United.

In accordance with the new loan rules, Ferguson will not be permitted to make any ‘emergency’ signings after the transfer deadline - but he has vowed not to make any panic additions.

“I think I’ve got to be patient,” Ferguson said on Monday.

“I have got other defenders, and there are other areas of the pitch I may want to strengthen before the window shuts.

“So we’ll wait and see.

“It is a blow because we seem to be losing defenders - Baudry, Alcock, Wright for a period, now Mason - so it’s hard to get a consistent back four or back three.

“But we have to get on with it.

“Others have to step up now and try and stay in the team.”

He added after the game on Tuesday: “The 18 players we had tonight is probably going to be what we’ve got for the next few games at least.

“We’ve got a couple of young ones on the bench.

“Unfortunately we keep on picking up these injuries.

“It’s nothing to do with the way we’re training, they’re all impact injuries.

“We can’t just keep on bringing players in and bringing players in.

“What we have to do is make sure we’re in a decent enough position by the time some of the more experienced players start coming back.

“If you look at what we have out injured at the moment, there’s a lot of experience there.”

Ferguson also confirmed he still hopes to sign a ‘different sort of striker’.

“I’m still looking for a striker that’s quicker [than what we’ve got].

“That’s been the case from day one.

“We’ve got targets and we’re hoping to get one before the deadline.

“I need to add a different sort of striker.”