The Nationals will be without closer Jonathan Papelbon for the foreseeable future, as the veteran right-hander was placed on the 15-day disabled list Tuesday. The move is retroactive to June 13.
Papelbon has been diagnosed with a right intercostal strain. Intercostals are muscles that surround the ribcage.
Right-hander Matt Belisle was activated off the 15-day disabled list to take Papelbon's place. Belisle is returning from a right calf strain. He has a 1.50 ERA in seven appearances this season.
Papelbon sustained the injury while warming up before his last appearance on Sunday. He allowed a ninth-inning homer to Maikel Franco in a game the Nats ended up winning on a walk-off single by Jayson Werth.
Papelbon, 35, was deemed unavailable in the Nationals' Monday night win over the Cubs. They instead used right-hander Shawn Kelley for a five-out save in the victory.
Papelbon has only pitched three times this month, having also tossed an inning on June 5 and June 10. He has 16 saves this season and a 3.28 ERA in 25 appearances.
This is the first time Papelbon has landed on the disabled list in 12 MLB seasons.