Phelps tweaked his oblique while taking batting practice on Tuesday, and initially he hoped he would miss maybe one start. If the injury had occurred on Thursday, or during the September callup period, he could have avoided a DL stint because rosters expand.
"I actually did it in the batting cage [Tuesday] in BP, like we take every day," Phelps said. "The first swing, I just felt something, shut it down. My initial reaction, my initial thought was maybe miss one start. Our initial reaction was [to] see how it feels in the morning and test it out today. That was the plan."
On Wednesday morning, Phelps still felt some discomfort, so he was placed on the DL.
Esch is the Marlins' 10th-rated prospect by MLBPipeline.com. The 26-year-old right-hander was recalled from Triple-A New Orleans.
Phelps, 29, has been one of the Marlins' best and most versatile pitchers, posting a 7-6 record with a 2.52 ERA in 55 games (five starts). The veteran has assumed a number of roles, going from long reliever earlier in the season to a setup spot, and he even has three saves. His DL stint is retroactive to Saturday.
"It seems like we caught it early enough," Phelps said. "We're thinking maybe four days and then start throwing again. That's the plan as of now. My arm is perfectly healthy. We're going to make sure these symptoms are out and go from there."
Due to other injuries on Miami's staff, Phelps was moved into the rotation. In five starts, he has gone 2-1 with a 2.22 ERA. In 24 1/3 innings as a starter, he has struck out 32 with 10 walks.
But in Phelps' most recent start, he worked just 3 2/3 innings on Friday against the Padres. His velocity dipped in that game, but he said it was due to mechanical issues.
"I threw a bullpen [session] the other day, everything felt really good," Phelps said. "The other day playing catch, I got out to about 120 feet, and I really felt the ball coming out on a better line. I was really looking forward to throwing today. It's amazing that stuff like this happens."
Esch had been a candidate to be called up in September. He opened the year at Double-A Jacksonville, where he was 10-9 with a 4.03 ERA in 22 starts. At New Orleans, he made four starts and was 2-1 with a 5.70 ERA.
Phelps is Miami's third starting pitcher on the disabled list. He joins lefties Adam Conley (third left finger tendinitis) and Wei-Yin Chen (left elbow).
"We were really fortunate in the first half, and we didn't really deal with a whole lot of stuff," Phelps said. "It's 162 games, stuff happens. A lot of times the teams that wind up there in the playoffs or in the World Series are the teams that are more resilient, and don't deal with stuff like this. We've got a good group of guys in here. We've fought all year. I don't think that's going to change.
"We're one good week away from being right back in the Wild Card. We've got to keep fighting. The tide is going to turn at some point."