LOS ANGELES -- The Marlins placed right-hander Tom Koehler on the 10-day disabled list Thursday, retroactive to Wednesday, the result of right shoulder bursitis.
By placing Koehler on the DL, the Marlins have pivoted from their original decision to option him to Triple-A New Orleans. Koehler had been sent down following his Tuesday start against the Astros, when he allowed eight runs in three innings to raise his ERA to 7.04.
Koehler underwent an MRI Thursday that revealed the injury, and Marlins president of baseball operations Michael Hill transferred him to the DL, manager Don Mattingly said before Thursday's series opener against the Dodgers.
Koehler, 30, has struggled to work deep into games. In eight starts, he's twice completed six innings. Koehler will be shut down from throwing for a week, Mattingly said.
The Marlins are also without left-handed starter Wei-Yin Chen, who has been on the DL since May 5 with left arm fatigue and has a partial ulnar collateral ligament tear.
While there are no current plans for Chen to undergo a second MRI, Marlins team doctor Lee Kaplan is consulting with renowned orthopedist Dr. Neal ElAttrache, who is based in Los Angeles.
"I know the doctors are talking about what our next steps are," Mattingly said. "I haven't heard the second opinion thing. I just know he came out, and Dr. Kaplan and Neal are kind of associates and they work together, so I know the doctors are going to be talking and be discussing which way we go from here."
With two starters out for an extended period, the Marlins are in need of a starter for Sunday's game. Mattingly said the club has not determined who will start, but mentioned Odrisamer Despaigne as an option, along with David Phelps or using just relievers.
"It really depends on what happens with our 'pen over the next few days," Mattingly said.
Phelps has been dependable out of the bullpen, and he and the Marlins have both said any move to the rotation would preferably be permanent for the remainder of the season.
"If it were to happen, it's something we have to be smart about," Phelps said.
Tuesday's announcement that Koehler would be optioned was a surprise, as he had been in Miami's rotation since 2013 and made at least 31 starts in each of the last three seasons. He began 2017 as the club's No. 3 starter.
"I've dealt with adversity my whole baseball career," Koehler said. "That doesn't stop now. I truly believe I belong in the big leagues. I've shown that. I've done this a long time now. It's just getting back to what I do well, and getting back to finding ways to help this team win."
• The Marlins outrighted infielder Steve Lombardozzi to New Orleans, after he was previously designated for assignment Tuesday.