SAN DIEGO -- Catcher Nick Hundley wasn't in the Padres' starting lineup on Wednesday against the Royals, missing his fourth consecutive game after he had fluid buildup in his right elbow from irritating a tendon.

Hundley is expected back for the Padres on Friday against the Mariners, but if for some reason the team needed him on Wednesday, he said could be play.

"He could maybe play [Wednesday]," Padres manager Bud Black said. "I'm going to check on his status after he plays catch and throws. He could be available, depending on how he comes out of this throwing session and hitting."

Hundley missed 31 games earlier this season with a right-oblique strain, but said the fluid buildup in his elbow was just due to the everyday toils of being a Major League catcher.

Hundley was certainly glad the elbow soreness wasn't anything worse.

"Definitely a relief," Hundley said.

Before doctors drained Hundley's elbow, the 27-year-old couldn't straighten it. Hundley said he couldn't even brush his teeth with his right hand, and it even made showering difficult.

Now his elbow has full range of mobility.

"I feel good," Hundley said. "I think that the target is to play Friday, maybe [Wednesday] in late innings if they need me. It feels good."

That's something that Black likes to hear.

"That's awesome," he said.

Gregerson close to making rehab assignment

SAN DIEGO -- Reliever Luke Gregerson, on the disabled list since June 9 with a strained oblique, had a bullpen session before Wednesday's game against the Royals, one that his manager hopes will get him on the road to rejoining the team.

Gregerson, who missed his 21st consecutive game on Wednesday, has now thrown three bullpen sessions since suffering the injury. If he feels no pain on Thursday, he'll begin a rehabilitation assignment with Triple-A Tucson on Friday.

San Diego manager Bud Black said that Gregerson -- the Padres' seventh-inning specialist -- would throw one inning for Tucson in a game on Friday in Sacramento. Gregerson would then likely do so again on Sunday.

"We'll evaluate from there," Black said. "There's a chance that he could join us in San Francisco."

The Padres will begin a three-game Interleague series in Seattle against the Mariners on Friday before opening a four-game series in San Francisco on Monday.

Gregerson hasn't felt the same pinch he felt warming up in the bullpen June 8 during a game against the Rockies.

"It's been feeling really good, the motion feels really good," said Gregerson, who was 2-1 with a 2.63 ERA in 30 games before the injury.