Conor Grant and Craig Alcock are facing a race against time to be fit for Doncaster Rovers' clash with Grimsby Town this weekend.
Full back Alcock was withdrawn during the second half of Sunday's defeat to Plymouth Argyle and is struggling with a calf issue.
And midfielder Grant - on loan from Everton - picked up a groin issue during the same game.
Both have yet to train so far this week and boss Darren Ferguson said their availability for Saturday's trip to Blundell Park rests on whether they take part in training on Thursday.
"Craig just took a knock on his calf and he was struggling at half time," Ferguson said. "I wanted to see how he coped at the start at the second half and you could see he was struggling.
"Conor Grant has got a knock to his groin.
"The haven't trained on Monday or Tuesday.
"There's a few bruises after the weekend but those are the only two who there is a doubt to train on Thursday.
"I'm not sure they will actually train on Thursday.
"If they don't train until Friday, that will give me a decision to make because that will be a whole week missed."
Should Alcock fail to regain fitness, Ferguson could opt to hand Luke McCullough his first start of the season after his incredible return to action last weekend.
McCullough came on for Alcock with 35 minutes to play on Saturday, just eight months after suffering knee ligament damage.
The Northern Ireland international played in the defensive midfield role with Niall Mason dropping in at left back.
And Ferguson insists McCullough is ready to start a game.
He said: "Luke is ready, there's no question about it.
"It was an easy swap with Niall going in there for Craig and the only decision I had to make is would it be Luke or Harry Middleton coming on.
"I thought McCullough physically would handle it better.
"He looked good. It might be a different game against Grimsby because we had a lot of comfortable possession against Plymouth whereas I think Grimsby are going to be a lot more aggressive.
"Certainly in their game at the weekend, they were quite aggressive in the way they pressed."