The summer capture from Blackburn Rovers twisted his right ankle in the 80th minute of the Victory Park clash which PNE won 2-1.
He was helped off the pitch by physio Matt Jackson and later left the ground walking with the help of crutches.
North End assistant manager Glynn Snodin said: “He just rocked his ankle and a little bit of swelling has come up.
“We have got a good medical team here and they are on it, they have already compressed the ankle and will assess it from there.
“Hopefully it will just be a few days and Tommy can get back to his work.”
Second-half goals from Joe Garner and Jordan Hugill gave PNE the win over the Magpies, Josh O’Keefe having fired the home side in front from the penalty spot with just a minute played.
It was a different Preston XI in each half, the second-half team performing better than the one in the first 45 minutes.
Snodin said: “We use the pre-season for fitness and it was another good work out.
“In the second half we looked a lot more sharper and lively than we had done in the first half.
“There was some good movement from the front three in the second half, plenty of crosses put into the box.
“In the first half we didn’t quite get into the thick of things with regards the intensity.”