As it turned out, Flynn's stay was just for one game. After he logged three innings of relief in Miami's 9-5 loss to the A's on Friday night, the lefty was sent back to New Orleans.
Miami will make a corresponding move before Saturday's game. A pitcher is expected to get the call. Sam Dyson, at New Orleans, is a likely candidate because he is on the 40-man roster and already had one callup this year.
For the first time this year, Miami is carrying 13 pitchers and 12 position players.
"We needed an arm after [Thursday] night," manager Mike Redmond said. "We had a couple of guys throw a lot of pitches. So we definitely needed an arm here, especially having a couple of young guys throwing the next few days."
In Thursday's exhausting marathon, Miami pitchers combined to throw 227 pitches, including 92 from starter Tom Koehler.
Reliever A.J. Ramos threw a career-most 50 pitches in 1 2/3 innings, and Chris Hatcher logged 44 pitches in 2 1/3 innings. Both were unavailable for Friday.
Miami will try to stay away from using Ramos for the entire series with the A's. At minimum, he will not be available on Saturday either.
Ramos has appeared in 39 games, and he hadn't thrown more than 33 pitches in any outing. The 33 came on June 15 against the Pirates.
Hatcher's career high for pitches is 55 in 1 2/3 innings against the Red Sox on June 20, 2012.
"We've got to get through this weekend, and then we have the off-day," Redmond said. "It just made sense because we know we have a couple of guys who are unavailable."
At New Orleans, Flynn was 7-5 with a 3.56 ERA in 16 starts, and he's thrown 91 innings. His last start was last Saturday, when he threw 5 2/3 innings.
Flynn actually was slated to start for the Zephyrs on Friday, but he was told at about 11:30 p.m. ET on Thursday that he would be heading to Miami. Flynn entered in the fourth inning on Friday, after Anthony DeSclafani was lifted due to a right forearm contusion. The lefty gave up two runs in three innings. He was in line for his first big league win, but that disappeared when the A's rallied in the eighth to tie the score at 5, before putting up four more in the ninth.
Last year, Flynn, who's ranked No. 6 among Marlins prospects according to MLB.com, gained some big league experience, going 0-2 in four starts with Miami, posting an 8.50 ERA in 18 innings.