"He's on his way," Towers said before Saturday's Interleague game against the Indians.
Headley, the converted third baseman who is in his first season playing the outfield, was hitting .305 with 13 home runs and 40 RBIs in 65 games for Triple-A Portland.
Headley flew Saturday from Fresno, where the Beavers were playing, to Cleveland. He wasn't expected to be in uniform until Sunday at the earliest or possibly Tuesday, when the Padres open an Interleague series at Yankee Stadium.
Towers did say that Headley will be in Cooperstown, N.Y., on Monday for the Hall of Fame Game that will be played against the Cubs.
"I think the environment is much better than it was three weeks ago," Towers said. "We have got a lot of guys contributing offensively. When he gets here, he shouldn't have to feel like he's got to carry this ballclub. We're playing good baseball now.
"To me, now is kind of the right time to have him here, when things are going well."
Headley, who had a .383 on-base percentage at Portland, is a switch-hitter who hit .330 with a .437 on-base percentage with Double-A San Antonio a year ago to earn Texas League MVP honors.
This season, Headley bounced back after a slow start (.242 batting average in April) by hitting .357 in May. He was able to cut down on his strikeouts, hit with more power and took more walks, which more or less matched his professional profile.
"If you look at his Minor League career, it's always taken him a while, a month to two months into it, his numbers pick up," Towers said. "... His numbers have been pretty consistent during his college career and his Minor League career. I think that's what's so attractive.
"He's never really had a down year. How that translates up here, I wouldn't be surprised if there's a learning curve here, where it takes him a while to get familiar with the pitching and the ballparks, learn the pitching staffs."
Headley nearly made the team out of Spring Training, but the Padres opted to let him get more time in the outfield with Portland. Headley had been a third baseman up until this season.
Headley has played a handful of games at third base at Portland and will likely see time there as well as left field for the Padres.
"He would allow us to give [third baseman Kevin Kouzmanoff] a breather," Towers said, noting Kouzmanoff has had but one game off all season.
The Padres will have to make a move to accommodate Headley on the 25-man roster, and it will likely involve an outfielder.
Towers admitted to a sense of tempered excitement over promoting a top prospect that was drafted and developed by the Padres.
"He's kind of been our, the last two years, top prospect in the system," Towers said. "So it's always exciting when a [Jake] Peavy, an [Oliver] Ollie Perez, Khalil Greene ... when they finally get here. You've been waiting for that event to happen."
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.