Doncaster boss Sean O'Driscoll admits he has been impressed with his trio of trialists over the pre-season.
Quinton Fortune, John Oster and Jason Walker have all pitched up at the Keepmoat Stadium in a bid to win a contract for next season.
Experienced duo Fortune and Oster are both free agents as they look to get fixed up, while Walker has won a chance at the Championship club after impressing for Barrow in a friendly against Rovers earlier in the summer.
All three started, and impressed, against Rotherham at the weekend as striker Walker also etched his name on the scoresheet.
"We brought a couple of trialists in and they did well and a couple of the young lads came on - so we are a little bit threadbare at the moment. We could do with supplementing the squad but that is proving difficult," O'Driscoll told the club's official website.
"I thought that Jason did well against us at Barrow. The idea was to bring him in and see what he was like with the rest of the lads. I was a bit disappointed that it was spread all over the nationals because now, if we didn't take him, it would seem that it was because he was not good enough - which wouldn't be the case; it would be because we have similar players.
"However, he has done well and fitted in well with the rest of the boys and trained well all week. We'll try and keep him for another week, if Barrow let us, and then he'll play some part in the Grimsby game.
"Then, I think to be fair to everybody, we need to make a decision and decide what we are going to do. But, Jason's put himself in the shop window and there must have been some people watching this game thinking that if he doesn't sign for us then this kid can do something. I'm pleased for him."
O'Driscoll will have to make a similar decision over midfield pair Fortune and Oster.
"John Oster had a back injury at the back end of last season and hasn't done anything for three months," he added.
"We were aware that he had no club, so he just came in to train and - again - he's another player that has probably put himself in the shop window, so we'll have to wait and see what opportunities arise for John.
"Quinton came to us to train and then went back to Birmingham, because they wanted another look at him. He wanted to come back and get some more training in and we were happy to oblige.
"Both boys have fitted in really well and have been a pleasure to work with."