Less than a week after returning to action, Dickerson was sent back to the 15-day disabled list on Wednesday. The Rockies also called up reliever Justin Miller from Triple-A Albuquerque and sent right-hander Jordan Lyles to the 60-day DL, which made room for Miller on the 40-man roster.
"Corey is very frustrated," Rockies manager Walt Weiss said on Wednesday. "I think we all know the type of player and the type of person Corey is. This is the last thing he wants, but I think deep down, he's knows that this is what's best for him."
Dickerson returned from the DL on June 11 and started the first three games in Miami, but he left Saturday's game after pulling up on a sixth-inning ground out. Dickerson didn't play the field and had just six at-bats the rest of the road trip.
As for now, his immediate future remains cloudy. Dickerson said he'll be back in a walking boot, but that surgery still isn't being considered. Weiss, however, said he has "no idea" when Dickerson will return.
"It did feel better after awhile, but after I played a couple games in Miami, it just didn't recover as well." Dickerson said. "It's kind of that back-and-forth. It feels good one day and hurts the next. It won't get better until it has time to rest.
"When you have tears or whatnot in your plantar fasciitis, you have to let it scar-tissue over and let it heal. But I just didn't really have enough time to do that."
Dickerson's injury leaves the Rockies with just four healthy outfielders, but Weiss said the plan was to call up pitching all along. Miller appeared in eight games for the Tigers in 2014 and had a 3.24 ERA with Albuquerque this season.
"We've rolled with seven in the 'pen for a little bit, and it's time to go back to eight," Weiss said.
Dargan Southard is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.