Grimes will be sidelined for the next six to eight weeks, and in a moonboot for the next fortnight after he suffered a stress fracture in his metatarsal bone.
It is understood the important defender suffered the setback because he was compensating for an existing toe injury when running, putting pressure on the outside of his foot.
Grimes was sidelined for long periods through 2011 and 2012 with hamstring injuries, but his latest setback will not influence contract talks, which are ongoing.
"He'll be in a moonboot for a week or two and then it just needs time to heal really," general manager of football Dan Richardson told AFL.com.au.
"He'll obviously keep himself fit with upper body stuff, but he's got to be careful about putting too much load on his foot.
"It won't be long until he's up walking and able to do some work on the machines we've got in the gym that decrease the amount of pressure through his feet."
Grimes has played just 22 games since he was recruited in the 2010 NAB AFL Pre-Season Draft (No.2 overall), but he has shown great promise as a key defender when available.
He has played five games this season, the last against Geelong in round six.
Richmond captain Trent Cotchin emphasised Grimes's importance to the team on Thursday, both as a player and a young member of the Tigers' leadership group.
"It's been really challenging for him and he hasn't played a lot of footy, but we see him as such an important player to our structure," Cotchin said.
"Last year when he was injured he went and watched a number of VFL games and filmed particular players that played in similar positions to him and gave them direct feedback.
"The great thing about 'Dyl' is when he is injured he finds things that keep him involved.
"He finds ways he can impact the younger guys and fast track their development, which is exactly what we want out of our leaders at this club."
Nathan Schmook is a reporter for AFL Media. Follow him on Twitter: @AFL_Nathan
