The young midfielder played in the 1-0 win against Preston reserves and had to go off injured just after half time with an ankle problem.
And when Wednesday are crying out for bodies at a vital part of the season, initial indications look like that McMahon could not be part of the play-off run-in.
After the Hartlepool game, he told Footymad: "It was the first time I played on Friday for five months and it's not been very pleasing being out to be honest but I have to get back to the form which I was in so I can give the team a boost for the last few games and give them some extra energy.
"I am still not 100 per cent match fit at the moment but hopefully when I get a few games under my belt, come on as sub or however the gaffer wants to give me a run out in the reserves that will come naturally."
This Saturday, the club welcomes Chris Turner back to Hillsborough and his Stockport County side who are leaving the division from the wrong end.
Turner was sacked by The Owls following a poor start to the season but Wednesday fans remember him from being one of the best goalkeepers in the club's history and without him in the summer, Wednesday would have been without the likes of Steve MacLean, Patrick Collins, JP McGovern, Chris Brunt and David Lucas.
But with Turner coming back, the law of the ex may strike. "They (Stockport) have nothing to prove now," admits McMahon. "Chris will have them up for a game which they will bill as a cup final because they have not played at Hillsborough that many times and I know that they will give everything because pride is at stake."