SAN FRANCISCO -- The Giants are having a rough couple of weeks, what with losing three players to the disabled list and going 0-4-1 in the past five consecutive series, but losing backup catcher Eliezer Alfonzo for a minimum of two months is especially painful.

Alfonzo, a reliable backup catcher and clutch hitter, suffered a grade-three sprain to his left posterior cruciate ligament Friday when he collided at the plate with Oakland's go-ahead run in the 10th inning. The PCL is located in the knee next to the anterior cruciate ligament, and a grade-three sprain (four being the worst) means the ligament came off Alfonzo's bone.

Alfonzo is seeking a second opinion from team orthopedist Michael Dillingham before deciding if he will opt for season-ending surgery. Even if Alfonzo forgoes surgery, he's looking a minimum rehab period of two months, head athletic trainer Dave Groeschner said.

"We don't see a lot of these. It's more of a football injury, but a lot of players don't have surgery. They let it scar down," Groeschner said.

Players who usually just let it scar down, however, aren't crouching on their knees for three hours a day. There's a higher probability of surgery for Alfonzo simply because he's a catcher.

There's also a risk that if Alfonzo tries to rehab, he will end up needing surgery in the long run anyway.

"There's a possibility that we'll try to rehab this, then down the line decide this isn't working," Groeschner said.

If it was an ACL tear, the decision to have surgery would have been easy, Groeschner said. The answer to a PCL sprain is not as obvious, and Alfonzo may seek a third opinion before making any decisions.

In the meantime, manager Bruce Bochy said recently called-up catcher Guillermo Rodriguez will get a chance in the starting lineup soon because Bengie Molina's legs could probably use a break.

Recovering Roberts: Dave Roberts got the day off Sunday after making his first Major League start Saturday since May 11 elbow surgery to remove bone spurs and chips.

Sunday was originally expected to be Roberts' return day, but Fred Lewis was put on the 15-day DL with a strained side Friday, so Roberts stepped up early.

Bochy said Roberts sat Sunday because he was trying to stack the lineup with righties. Roberts also got to rest because Barry Bonds was feeling good enough to play.

Roberts went 0-for-4 on Saturday, but had quality 10-pitch at-bats in his first two plate appearances. The high pitch count is even more impressive considering Roberts was facing Dan Haren, who leads the American League with his 1.58 ERA.

"His first game back, he faced a tough pitcher and I thought he battled well," Bochy said.

Groeschner said he's more worried about Roberts' arm while he's throwing, not batting.

Kline ties Spahn: Reliever Steve Kline tied Hall of Fame pitcher Warren Spahn for 16th on the all-time left-hander list with his 750th game appearance in the ninth inning Saturday.

"When I first started doing the whole reliever thing, people told me to take it easy or I'd blow out my arm, but I was always taught that I was paid to pitch," Kline said. "Let's see if I can get to 800 this year."

Puppy love: Ryan Klesko's puppy Gizmo made a guest appearance in the Giants' clubhouse for a good-luck sendoff before the Giants tried to avoid an Oakland sweep Sunday. Gizzy romped around with the players and loosened up the clubhouse mood.

"There's nobody here that should be tight. I don't know how you can be tight when you're in last place," Bochy said.

On deck: The Giants will open a three-game Interleague series against the Blue Jays on Monday, with Matt Morris (6-3, 2.51 ERA) on the mound against Toronto's Josh Towers (2-3, 5.15 ERA) at 7:15 p.m. PT.