A lack of match fitness is set to hamper Tom Bellchambers' AFL return from a year-long doping ban, with the Essendon ruckman's pre-season slowed by knee surgery.
The Bombers have put a two-month time frame on his recovery, ruling him out of pre-season games and putting him in doubt for their round-one clash with Hawthorn on March 25.
While his fellow formerly banned Bombers will have a pre-season campaign under the belt, Bellchambers will enter the round-one selection mix without having played under match conditions in 18 months.
He was sidelined with a foot fracture halfway through the 2015 season.
The 27-year-old has succumbed to a pre-existing knee complaint which flared under the rigours of pre-season.
"Tom Bellchambers, like Joe (Daniher), has a knee surface issue from a number of years ago that also raised its head before Christmas," high performance boss Justin Crow told the club's website.
"He was rehabbing up after a rest and progressing well until a week ago.
"He's not quite at 100 per cent so today we sought the advice of his specialist, Julian Feller, and Tom is going to go in for a clean-out of his knee to try to get him to 100 per cent.
"Tom will start running in a month. He'll build up his football over a month after that and then he'll be pushing for selection."
Bellchambers had an enforced year in the AFL wilderness due to his involvement in Essendon's 2012 supplements program.
Crow said star forward Daniher, who's recovering from a similar knee issue, should be fit in time for pre-season games.
"We've got to find the balance between filling Joe's tank up for the season and also getting him to the point, from a football point of view, where he's ready to play at a high level," he said.
"We'll be weighing that up as we go but I'd be thinking more the later end of the (JLT) Community Series, than the front end."