Formers Rovers players Chris Brown and Gary McSheffrey have been training with the club.
They have been taking part in pre-season to maintain fitness ahead of the new season.
Rovers boss Darren Ferguson said: “Browny’s not played for a year so he needs to get a bit of fitness going. I think he’s just seeing if he can get through pre-season.
“He’s a good lad and I’ve got no problem with him coming in and us helping him out. The same with Gaz, who is just building up his fitness with us.”