INJURY-RIDDLED St Kilda midfielder Nathan Freeman will begin running on Thursday ahead of a planned comeback in six weeks after surgeons found a defect in his hamstring. 

The 22-year-old was operated on a fortnight ago.

"The good news is they found a bit of a defect there and repaired that. He's probably six weeks away from playing," St Kilda head physiotherapist Andrew Wallis told saints.com.au.

"He starts running on Thursday, so he's pretty upbeat about that. He hasn't actually missed too much training, so the good news is his conditioning is right up there."

Since being drafted at No.10 in 2013 by Collingwood, he has not played a game.

Freeman had been in contention to line up in one of the JLT Community Series matches after having a largely faultless pre-season, other than a calf niggle at the end of last year.

He managed 13 VFL matches last year.

Meanwhile, draftee Ben Paton went under the knife for a thumb issue suffered in a practice game for Sandringham against the Northern Blues last week.

"They normally miss about six weeks but we hope to get him back a whisker earlier," Wallis said.

Ruckman Ben Longer has an issue with his left hip flexor. He may have been available to face Melbourne at Casey Fields if the match was later in the week and is expected to be fit for round one against Brisbane.

"He probably could have got up for this week but being a Thursday game, we thought we'd take a little bit longer. He's just a week away," Wallis said.