Peter Shirtliff is giving trials to two overseas goalkeepers at Mansfield after Jason White had an operation on his troublesome knee.
White experienced some pain in the knee during pre-season training and the club opted for minor surgery.
Stags boss Shirtliff is expecting White to be fit for the start of the new season - which kicks off at Shrewsbury on August 5.
But he is taking no chances and will be using the pre-season games to take a look at two keepers, one from Poland, the other from South Africa.
"Jason's operation will basically clear out his knee, " said Shirtliff.
"It is not a problem from last season, but something that has become apparent since he reported back
"He has been working with former Forest coach (and ex-Stag) Andy Beasley but it was obvious it was not quite right and it's better that it gets fixed.
"The two trialists have been offered to me by an agent. I don't know what they will be like, but you never know..
"Hopefully, Jason will be back before the start of the season anyway. There should be no problems."