SAN FRANCISCO -- Catcher Nick Hundley will head to San Diego on Friday to have arthroscopic surgery to remove loose particles in the troublesome right elbow that has given him fits for the last 10 days.

Hundley, who missed 31 games on the disabled list earlier this season with a strained right oblique, is expected to miss between three and six weeks. The surgery will be performed in San Diego.

"It's pretty straight forward," Padres manager Bud Black said.

The Padres will add catcher Luis Martinez to their roster on Friday, and he's expected to be in uniform when the team opens a three-game series against Los Angeles at Dodger Stadium.

Martinez is hitting .313 with Triple-A Tucson.

"I had three options -- keep going, shoot the elbow up [with cortisone] and take a week to 10 days and see what happens or have surgery," Hundley said. "But the way that it's been going, there was no way of knowing if or when it would lock up on me."

Hundley missed four games last week with what the team called an irritated tendon in the elbow. He returned Friday to play in Seattle, but the pain in the elbow would come and go -- sometimes it felt fine, sometimes he couldn't bend it.

"There's times when it locked up when I was answering the phone or brushing my teeth," Hundley said. "There are some loose bodies floating around in there, some cartilage that we need to take out.

"If I knew it was going to get better, I'd play through it, but it's not getting better. And at some point, I'd be shut down because of it. I didn't think it was fair to the team if I kept playing."

Which is why Hundley, who is hitting .222 with three home runs and 15 RBIs over 153 at-bats this year, will have the surgery now, with the hopes of still returning this season.

"It's unfortunate, because he got off to a good start and then got banged up," said Padres catcher Rob Johnson, who will handle the primary catching duties with Kyle Phillips. "[Being injured] is a frustrating thing. But Nick has a positive spirit. He'll get through it."

Hundley said he first felt soreness in the elbow while catching against the Braves on June 25. He later had a cortisone shot and an MRI that showed no structural damage.

Rizzo confident despite recent struggles

SAN FRANCISCO -- It's been nearly a month since rookie first baseman Anthony Rizzo made his Major League debut with San Diego on June 9.

It's been a month filled with significant firsts as well as growing pains that other players his age -- Rizzo won't turn 22 until Aug. 8 -- go through in their first stint in the Major Leagues.

"I had that success right when I came up, and it seems no matter what level I've been at, I've had success and then I kind of subconsciously try to do too much with my swing," Rizzo said.

Rizzo had a hit in his first game with the Padres, the same day the team added him to the roster from Triple-A Tucson. Two days later, he hit his first home run.

Rizzo then saw his batting average drop to .158 after a hitless game against the Red Sox -- his old organization -- on June 22. He's hitting .171 with 28 strikeouts and 12 walks in 25 games. Nine of his 13 hits have gone for extra bases.

"In my bad at-bats, where I'm striking out, I'm walking back to the dugout thinking that I should have crushed that," Rizzo said. "This game is humbling, but I know that I belong here. It's a matter of taking your confidence to the field every day."

Rizzo said he was encouraged by his game Monday against Giants pitcher Tim Lincecum, when he reached base three times -- with a double, walk and when he was hit by a pitch.

"A game like that against a pitcher like Lincecum gives me confidence," Rizzo said.

Harang set to return from DL on Saturday

SAN FRANCISCO -- Aaron Harang will be reinstated from the disabled list in time to make a start against Los Angeles on Saturday at Dodger Stadium.

Harang has been on the disabled list since June 13 (retroactive to June 10) with a fracture of the third right metatarsal in his right foot.

Harang threw 70 pitches over four innings in a Minor League rehabilitation start on Monday for Class A Lake Elsinore.

"The foot, in his words, is a non-issue," Padres manager Bud Black said.

Harang threw a normal side session with Lake Elsinore on Wednesday and will meet the team at Dodger Stadium on Friday.

Black originally thought that Harang -- who is 7-2 with a 3.71 ERA in 13 starts this season -- might need two rehab appearances before rejoining the team. But when Harang's foot responded well to two workouts last week in Seattle, it might have changed his timetable.

"Prior to that start in Lake Elsinore, he showed a lot of improvement. There was no pain in the foot in his baseball activities so ... get him back on the horse."