EMERGING Essendon ruckman Tom Bellchambers could get an opportunity to add to his three senior games as early as round one, with Jason Laycock suffering another setback to his fractured foot.

Laycock, 24, has missed a large part of the pre-season after battling problems with his navicular bone and recently underwent surgery to remove a screw from the area.

He has since suffered a "reaction" to the operation, which has left the Bombers unsure just when the 58-game player will return.

"He's had a stress reaction in his navicular joint, which is where he's had the problem and where he had the operation," football operations manager Paul Hamilton said on Thursday.

"We've just got to rest him, as that's all we can do. We'll rest him for four weeks, get another MRI (scan) and find out where he sits.

"It's disappointing for Jason. He was really hopeful to be up and going by now, and so were we, but he's just had setback after setback over the course of the pre-season."

Hamilton said the initial break of the bone has mended but the reaction to the operation has left Laycock in limbo.

"The fracture is completely healed, the MRI shows that, but he's had a little bit of a reaction," he said.

"With that reaction, you can't do very much at all. You just have to wait and put it in a moon boot and let healing take its course.

"There's not a lot of things we can do to help him. It's just time."

Bellchambers,19, has played all of the Bombers' NAB Cup matches so far, and will get another opportunity to stake his claim on Laycock's vacant back-up ruckman position come Friday night when the club faces North Melbourne in the NAB Challenge in Bendigo.

"He's been doing a really good job and we're happy with his progress," Hamilton said.

"He's a second-year boy and we think he's got a lot of potential.

"He's one of our options for round one. Not the only one, as we've got a number of players we can put into the ruck but, at the moment, he's the one that will get the opportunity tomorrow night.

"If he can really play well, we know that the round-one Port Adelaide ruckmen are two of the best going around in the AFL so it's a chance for Tom to put his best foot forward and play some good footy."

Experienced midfielder Mark McVeigh could still be considered for round-one selection, depending how his injured ankle reacts to running next week.

"We're hopeful with Mark. He starts running next week and it's a case of if he's got no pain, he can build up very quickly, which means he could be available for round one," Hamilton said.

"If he has pain when he starts to run next week, then we'll hold back a little bit.