SAN DIEGO -- Mark Prior's offseason pitching program and recovery from his shoulder surgery 10 months ago have gone so smoothly that it appears as if he could be pitching in the Major Leagues as early as May.

Speaking at the San Diego Hall of Champions luncheon on Thursday, San Diego general manager Kevin Towers said that Prior -- the San Diego native who signed a one-year deal in December -- is progressing nicely from his shoulder surgery.

"Hutch [trainer Todd Hutcheson] told me that if he keeps along with the progress that he is having now, that he could be ready for a [Minor League] rehab [assignment] when we start our season," Towers said.

The Padres open the regular season at PETCO Park on March 31, which is about the time they would like to send the right-hander on a Minor League rehabilitation assignment to test his shoulder over six or seven starts.

"He's just started getting up on the mound," Towers said of Prior's offseason program, one that has him throwing regularly with closer Trevor Hoffman. "He's no longer just throwing on flat ground."

"Absolutely, things are going well," said Prior's agent, John Boggs. "He's worked hard at his rehabilitation to get prepared. Things are certainly on a positive trend right now."

Does Towers really think Prior -- who won 18 games for the Chicago Cubs in 2003 but has been besieged by injuries since -- can be ready to pitch in a Padres uniform in May?

"There's a chance. I don't know how realistic that is," Towers said. "But initially we had thought it would be the first of July."

Clark, not Sweeney? Towers and manager Bud Black will head to Peoria, Ariz., next week for the start of Spring Training but that doesn't mean Towers is finished tinkering with his roster.

On Tuesday, veteran Mike Sweeney, a five-time All-Star with the Royals, worked out at PETCO Park. The Rancho Santa Fe resident took batting practice and ground balls and spent time taking fly balls as well.

"It's kind of awkward to have a four- or five-time All-Star working out for you," Towers said. "He's a great guy."

But Sweeney might not be the best fit for the Padres, as Towers indicated that the team is working to get a deal done with 35-year-old Tony Clark, who played last season with the Arizona Diamondbacks and is a former San Diego State Aztec.

Clark is a switch-hitter familiar with National League pitching, and he more or less killed the Padres last season (four home runs in 26 at-bats). He is also receiving interest from Cincinnati and Los Angeles.

Clark, who hit 17 home runs last season with the Diamondbacks, can play first base and would give the Padres another pinch-hitting option late in the game.

Clark would also give the Padres a designated hitter for when they play Interleague road games in Cleveland and against the Yankees this season.

Boggs, the agent for Clark as well as Prior, said Thursday night, said it's "50-50" as to whether his client signs with the Padres.

"If it came to fruition that Tony played in San Diego, he would be very happy," Boggs said. "The Padres have put forward the positive aspects [of playing for San Diego]. Hopefully we are moving forward."

About Khalil: The two-year contract for Padres shortstop Khalil Greene could officially be announced Friday -- and no, we're not kidding.

The deal for a reported $11 million that will keep Greene from arbitration was close on Saturday and one media outlet went as far to say it was a done deal. Not so fast, though.

Towers said there's some "language issues" in the contract that have prevented the deal from getting done, though that's not uncommon, he said.

"It's a done deal," Towers said.

Towers said the Padres pushed for a three-year deal and a four-year deal with Greene only to be rebuffed by his agent. "The difference," Towers said, "is dollars."