Doncaster manager Dean Saunders is hoping to make "three or four" new signings next week.
Saunders also confirmed after his side's goalless draw with Sheffield Wednesday on Saturday that defender George Friend was poised to complete his move to Middlesbrough.
"I think George has more or less agreed to go to Middlesbrough, so that will probably be happening on Monday," Saunders told the club's official website.
He added: "We knew we had to get some players out, I would have liked for it to have happened earlier but it didn't so we have just got to do our best. It's been a difficult summer, but players are starting to come into the market now that we didn't know were available.
"Players come back into pre-season thinking they're in with a shout of playing, then they quickly find out they're not and they come on the market.
"By that time some of the other teams have already spent their money - sometimes you can pick up some really good players that you didn't expect to be on the market and I think we've got a couple of them coming in."
- Dean Saunders
- George Friend