Mathieu Baudry is set to miss the start of the season after having an operation on his Achilles.
The 28-year-old defender was troubled by the injury from virtually day one of pre-season and has since gone under the knife.
He is now almost certain to miss Rovers’ busy start to the new season next month, when they face five games over the first two weeks.
Baudry’s reputation as a cultured centre back and also his experience of captaining Leyton Orient marked him out as a key summer signing - and someone likely to be jettisoned straight into Doncaster’s new-look back four or back five.
With boss Darren Ferguson still to confirm this season’s skipper, Baudry may have also been in the running for the armband.
However, the Frenchman’s injury setback leaves Andy Butler, Joe Wright, Craig Alcock and Luke McCullough to battle it out for the centre half spots for the League Two opener at Accrington Stanley on August 6.
Wright also sat out Tuesday night’s 4-0 win at Rossington Main and is most likely to come into contention for next Wednesday’s friendly with Newcastle United.
“Mathieu Baudry has had an operation on his Achilles which is obviously not good news,” Ferguson said.
“He’ll probably miss the start of the season.
“Joe Wright hopefully should be okay for the Newcastle game, and he’s got a chance for Middlesbrough. He’s just got a little tweak in his groin, that’s not a serious one at all.
“But Baudry is certainly going to be a little bit longer.”
Injured pair Paul Keegan and Gary McSheffrey, meanwhile, won’t return to full training for around ten days.
Luke McCullough is back today following his extended break.