However the 24-year-old winger returned to training this week and is in the squad to face his home-town club at Field Mill on Saturday at 3pm.
The news will be a boost for boss Paul Jewell, who has been without defenders Alan Stubbs and Claude Davis this summer due to injury, while Paul Connolly missed the recent Oldham game with a shin problem.
New striker Rob Hulse is expected to link up alongside Nathan Ellington in attack, while 29-year-old Oster should also play his third game on trial after featuring against the Latics and Rotherham.
"We may involve him at Mansfield and then we will speak and make a decision," said Jewell.
"If I was not interested in him as a player, he would not be here."




