Johnson (elbow) made his 2018 debut for Double-A San Antonio on Monday, tossing a perfect inning in relief in the affiliate's 9-1 win over Northwest Arkansas.

Johnson (elbow) signed a minor league contract with the Padres on Friday, Jon Heyman of FanRag Sports reports.

The Padres declined to tender Johnson (elbow) a contract Friday, making him a free agent, Dennis Lin of the San Diego Union-Tribune reports.

Johnson (elbow) underwent Tommy John surgery Thursday with Dr. James Andrews, the San Diego Union-Tribune's Dennis Lin reports.

Johnson was moved to the 60-day DL on Monday, Bill Center of Padres.com reports.

An MRI on Johnson's elbow Saturday revealed a flexor strain and he is expected to miss 3-to-6 weeks, Jeff Sanders of the San Diego Union-Tribune reports.

Johnson (elbow) was placed on the 15-day DL on Friday.

The Padres will either bump Johnson from the rotation next week or continue with a six-man rotation, MLB.com's AJ Cassavell reports.

Johnson (0-4) allowed four runs on seven hits with two strikeouts over five innings in a loss Tuesday to the Orioles.

Johnson (0-5) was bombed Wednesday for the third time in three starts as a Padre, giving up six runs on nine hits in four innings in a loss to the Orioles. He struck out three and walked one.