The Los Angeles Dodgers believe Clayton Kershaw could be back within two weeks, reports ESPN LA.
Kershaw has made just one regular-season start for the Dodgers so far this season during the Australia series against the Arizona Diamondbacks.
It was a strong start to his season, pitching 6 2/3 innings before complaining of tightness in his upper back.
He was originally placed on the 15-day disabled list but was soon diagnosed with a strained teres major muscle.
Following a long layoff, Kershaw is set to begin his rehabilitation assignment in the minor leagues at Class A Rancho Cucamonga.
Don Mattingly confirmed Kershaw will be in action on Friday but refused to speculate on how many rehab starts the pitcher may need before returning.
He told reporters: "We'll just go one at a time and see. More than one, for sure."
Kershaw has been throwing bullpen sessions for over a week now, also throwing a 55 pitch game simulation at the Dodgers Stadium on Sunday.
Mattingly said Kershaw will be limited to 60 pitches for Rancho Cucamonga.
"I don't think anybody's going to let him go out if we weren't allowing him to just go pitch," Mattingly said. "He hasn't felt anything since that one day. There's been no day in there that he's felt anything throwing a baseball."
Kershaw could return for the trip to Washington on May 5 if all goes well.