Morejon earned a save against the Pirates on Wednesday, striking out one batter in a perfect inning of work.
Morejon picked up a hold against Baltimore on Friday despite allowing two runs on three hits and one walk over two-thirds of an inning. He struck out one batter.
The Padres recalled Morejon from Triple-A El Paso on Friday.
The Padres optioned Morejon to Triple-A El Paso on Thursday, Dennis Lin of The Athletic reports.
Morejon signed a one-year contract with the Padres on Thursday, avoiding arbitration.
Morejon (knee) has made his last two rehab appearances at Triple-A El Paso, covering 1.2 innings and allowing an unearned run on one hit and no walks while striking out three between the two outings.
Morejon (knee) kicked off a minor-league rehab assignment with the Padres' Arizona Complex League club Friday, striking out two batters in one scoreless inning.
Morejon (knee) was placed on the 15-day injured list Sunday.
Morejon strained his right knee in the second game of Saturday's doubleheader against the Phillies and will be sent for imaging, Sammy Levitt of 97.3 The Fan reports.
Morejon will draw the start for Sunday's game against the Reds, Kevin Acee of The San Diego Union-Tribune reports.