- The Washington Nationals placed left fielder Bryce Harper on the 15-day DL, retroactive to April 26, with a left thumb sprain. The Nats recalled outfielder Steven Souza Jr. from Triple-A Syracuse to take Harper's place on the roster, according to a team announcement. Initial reports indicate that the extent of the injury is unknown, though Harper will see another specialist on Monday or Tuesday to determine the nature of the injury, per The Washington Post's Adam Kilgore.
- The Detroit Tigers placed right-hander Anibal Sanchez on the 15-day DL with a laceration on his right middle finger, the team announced. Right-hander Justin Miller was recalled form Triple-A Toledo to replace Sanchez, who has a blister on his finger and will likely miss a decent amount of time given the severity of the blister.
- The Baltimore Orioles placed first baseman Chris Davis on the 15-day DL, retroactive to April 26, with a left oblique strain, per a team announcement. The injury is a medium-grade strain, which means Davis might not be quite ready to return by May 11, when he's eligible to come off the disabled list. Davis is batting .250 with a .754 OPS and a pair of homers this season.
- The San Diego Padres activated center fielder Cameron Maybin from the 15-day DL, optioning Kevin Quackenbush to Triple-A El Paso, the team announced. Maybin went 2-for-4 with a double and a run scored in his first game back on Sunday as the Padres beat the Washington Nationals by a score of 4-2.
- The New York Yankees recalled Preston Claiborne from Triple-A Scranton/Wilkes-Barre and placed right-hander Bruce Billings on the 15-day DL, retroactive to April 26, with a right forearm strain, according to a team announcement.
- The Texas Rangers activated left-handed starter Matt Harrison from the 15-day DL and optioned Luis Sardinas to Double-A Frisco, according to Rangers VP of Communications John Blake. Harrison allowed three hits and a pair of runs over six strong innings in his debut on Sunday, but took a no-decision as the Rangers blew a late lead.
- The Los Angeles Angels optioned Brennan Boesch to Triple-A Salt Lake and purchased the contract of Mike Morin, the team announced.
- The Chicago White Sox optioned Erik Johnson to Triple-A Charlotte and purchased the contract of right-handed starter Scott Carroll, according to a team announcement. Carroll made his MLB debut on Sunday, allowing one earned run across 7.1 strong innings as he grabbed the win in Chicago's 9-2 victory.
- The Pittsburgh Pirates recalled right-hander Casey Sadler from Triple-A Indianapolis, optioning Jared Hughes to Triple-A, per a team announcement.
- The Los Angeles Dodgers recalled Carlos Triunfel from Triple-A Albuquerque and optioned Jose Dominguez to Triple-A, the team announced.
- The Philadelphia Phillies signed free agent Lars Davis to a minor league contract, according to MiLB.com.
- Rehab Assignments: Hisashi Iwakuma (SP, Mariners) to Triple-A Tacoma, Juan Lagares (CF, Mets) to Single-A St. Lucie, Brendan Ryan (SS, Yankees) to Single-A Tampa