RICHMOND defender Dylan Grimes has suffered a setback with his foot injury and will be sidelined for up to two months, continuing a luckless run for the highly rated backman.

Grimes was initially expected to miss two matches following the Tigers' round six loss to Geelong, but his best case return now appears to be the round 15 match against North Melbourne.

General manager of football Dan Richardson told that Grimes's foot had not responded as quickly as the Tigers had hoped and they would now take a conservative approach with him. 

The 21-year-old battled hamstring injuries in 2011 and 2012, missing 30 games because of injury in the past two-and-a-half seasons.

Fellow backman Ricky Petterd, who was initially expected to push for selection in Saturday night's 'Dreamtime at the 'G' clash against Essendon, will be sidelined for at least another two weeks with a calf injury.

The former Demon, who has also been sidelined since round six, will not be available until after Richmond's mid-season bye in round 11.

In better news, ruckman Ivan Maric (ankle) and veteran defender Chris Newman (groin soreness) are expected to be available for Saturday night’s clash against the Bombers.

Talented young midfielder Reece Conca completed a strong running session at the ME Bank Centre on Tuesday morning and is a chance to resume from a foot injury against West Coast in round 10.

Nathan Schmook is a reporter for AFL Media. Follow him on Twitter: @AFL_Nathan