Voltar
The Wrexham manager gave an update on Sheaf, who came on as a second half substitute in the 2-0 defeat at Blackburn Rovers last weekend.
He will also assess the fitness of Cleworth (hamstring) and Thomason (thigh) who are now back in training.
"Sheafy's trained well and he's made another step in the right direction," said Parkinson, whose side head to Sheffield United in the Championship on Friday night.
"Max and Thommo weren't with us on Saturday, but they've stayed here and trained, and they've had a good week on the training pitch.
"We've just got to now assess those two going into the weekend but, at the very least, they're strengthening up the numbers as we go into these three games in eight days."