McNulty, 25, is on loan at Glanford Park until January but has only appeared in four first-team games after suffering an ankle injury in August.
"Jim trained on Monday and [first-team coach] Steve Parkin said he got through the session okay," said Ian Baraclough, the Iron manager.
"It will take him a while to get back into the habit of training day-in and day-out but it's promising for us. "He'll need one or two reserve games first, and I don't know how long it will take him to make a first team return. You've just got to be careful."
He is unlikely to feature even be on the bench against Middlesbrough on Tuesday or Cardiff City on Saturday, but could play for the reserves against Grimsby Town at Glanford Park next Tuesday.
Rob Jones will also sit out against Boro due to his broken hand, as will Garry Thompson who is still lacking fitness following a groin injury.
Michael O'Connor, Josh Wright and Eddie Nolan are carrying slight knocks following Saturday's impressive 1-0 Humber Derby win at Hull City, but are expected to be in the matchday squad.
Cliff Byrne required three stitches below an eye after being on the receiving end of a rather agricultural challenge from Nicky Barmby during that game,