The Cincinnati Reds placed right-hander Emilio Pagan on the 15-day injured list on Thursday due to right triceps tightness.
In a corresponding move, the Reds selected the contract of right-hander Brett Kennedy from Triple-A Louisville.
Pagan last pitched on Sunday, when he recorded two outs in the ninth inning against the host Los Angeles Dodgers before exiting the game in the middle of Jason Heyward's at-bat and was replaced by Alexis Diaz.
Pagan, 33, had good results from an MRI on Monday, the team said, but the triceps issue did not improve and he was placed on the IL, retroactive to Monday.
"He woke up still feeling it today," Reds manager David Bell said Thursday. "Hopefully, it is short term. Nothing was found on the MRI, which was good, but the symptoms were there."
Pagan is 2-3 with a 4.19 ERA, seven walks and 25 strikeouts in 19 1/3 innings over 21 relief appearances this season.
In his eight-year career with the Seattle Mariners (2017), Oakland Athletics (2018), Tampa Bay Rays (2019), San Diego Padres (2020-21), Minnesota Twins (2022-23) and Reds, he is 24-21 with 32 saves, a 3.73 ERA, 121 walks and 481 strikeouts in 419 1/3 innings over 390 games (one start).
Kennedy, 29, was 1-5 with a 6.86 ERA, eight walks and 32 strikeouts in 40 2/3 innings over eight starts at Louisville. He has pitched in 11 major league games (eight starts) with the Padres (2018) and Reds (2023) for a 2-2 record and a 6.65 ERA.
In another move, Cincinnati designated outfielder Bubba Thompson for assignment. Thompson, 25, batted .111 in 17 games with the Reds before being optioned to Double-A Chattanooga earlier this month.