The team optioned outfielder Franmil Reyes to Triple-A El Paso in a corresponding move.
In his first game back, Myers was penciled in to play left field and bat leadoff Thursday night at San Francisco.
Myers had been out since April 29 due to a strained left oblique. That was his second trip to the disabled list this season; he previously missed time because of nerve irritation in his right arm and back soreness.
Myers, 27, was hitting .300 with one home run and three RBIs in 10 games this season before Thursday. He had six hits, one homer and three RBIs in five rehab games with El Paso. Myers is expected to be slowly worked back into the Padres' outfield mix.
"He might play two days, then have a day off," manager Andy Green told reporters. "He might play three days, then have a day off. We might carry that on for some considerable period of time to just ensure that he's in a good physical spot and ready to go before we unleash him to go on a very consistent basis."
Myers was an All-Star in 2016, when he hit .259 with 28 home runs and 94 RBIs for San Diego. He followed that up with his first 30-homer campaign in 2017.
Reyes hit .228 with six home runs and eight RBIs in his first major league stint. The large-bodied 22-year-old struck out 39 times in 92 at-bats.
The Padres made several other transactions before the Thursday game. Right-handed reliever Phil Maton, out since mid-May due to a lat strain, came off the disabled list, and right-hander Phil Hughes landed on the 10-day DL due to a right rhomboid strain.
Maton, 25, had allowed just one run in 16 innings (0.56 ERA) through 15 appearances before he went on the DL.
Hughes, 31, has no decisions and a 6.53 ERA in a combined 14 appearances, including two starts, for the Minnesota Twins and the Padres this year.
Colin Rea, who had been rehabbing with Double-A San Antonio, was activated from the disabled list and optioned to El Paso. Rea, 27, is still attempting to come back from Tommy John surgery he underwent after the 2016 season. He was 0-3 with a 7.13 ERA in six starts for San Antonio this season.
The Padres also transferred outfielder Franchy Cordero from the 10-day DL to the 60-day DL. Cordero had been out since May 28 due to a strained right forearm, and he experienced right elbow soreness Sunday while on a rehab assignment with El Paso. An MRI found the presence of a bone spur in his right elbow, and he is deciding whether to undergo surgery.
--Field Level Media