UPDATE 2-Sprint--Pre success will be clearer in 3-5 months

*Too early to tell if Pre is hit

*Sprint plans Android device for this year

*Hesse says impressed with Motorola’s Jha

*Sprint shares down 3 pct, Palm shares up 1.34 pct (Adds background, share price update, byline)

By Gina Keating

PASADENA, California, July 24 (Reuters) - Sprint Nextel Corp's S.N Chief Executive Dan Hesse said on Friday that it was too soon to say whether Palm Inc's PALM.O Pre phone would be a "real hit," and that determination could take until five months after launch.

The top executive of the No. 3 U.S. mobile service said the high-profile Pre’s June launch went very well, but initial supply constraints made it harder to declare Pre a big success yet.

“You won’t know if we have a real hit on our hands until its been out three months, four months, five months ... It’s too early to tell,” Hesse told the Fortune Brainstorm Tech conference. “We’re just getting it rolled out in decent quantities for direct distribution.”

Hesse said in response to a question that Sprint, the exclusive U.S. provider for Pre, has not seen a lot of returns of the device from customers who bought it.

Sprint, which has been struggling to stem customer defections for a few years, sees Pre as a key factor in its efforts to turn its business around.

The executive said that later this year Sprint's product line-up would include a device based on Android, the mobile operating system developed by Google Inc GOOG.O.

He did not which phone vendor would sell the device.

Asked his opinion on Motorola Inc's MOT.N chances for a recovery, Hesse said that he was "cautiously optimistic" because of work he'd seen so far from Sanjay Jha, who was brought in as CEO of the ailing cellphone maker last year.

Jha has turned the company’s focus to Android and its first phones on this platform are expected to come out this year.

“Some things I can’t disclose, but I’m pretty impressed on the handset side with what Sanjay’s has been able to do there since he’s been there, his team in terms of the road map on what they’re doing on the device side,” Hesse said.

Sprint shares were down 14 cents or 3 percent at $4.52 on New York Stock Exchange. Palm shares were up 15 cents or 1.1 percent at $14.31 on Nasdaq. Motorola shares were up 1 cent at $6.60 on the NYSE. (Reporting by Gina Keating in Pasadena, writing by Sinead Carew in New York, editing by Gerald E. McCormick)