The Blades face Donny tonight and boss Danny Wilson is expected to give three players an opportunity including McDonald, who was release by Eddie Howe at the end of last season having spent time out on loan at both Scunthorpe and Notts County.
Wilson will also give an opportunity to goalkeeper Iain Turner, who ended last season with Preston.
He said: “We’re hopeful both Kevin and Iain will play some part against Rovers. We want to make sure there’s competition for places across the board here.Be that competition is games or even in the sessions we do during the week because it keeps everyone on their toes and helps to raise levels of performance."