If Jeremy Affeldt could not laugh about being the king of freak injuries, he might cry. Before he heard one question about his latest trip to the disabled list, he said, "I was separating frozen hamburgers and I slipped on the floor."

Actually, Affeldt sprained the medial collateral ligament in his right knee Saturday night when his son Walker, a 4-year-old who already stands 4-foot-6 and weighs 60 pounds, leaped off the sofa and ran into Affeldt's arm when the pitcher got home.

Affeldt said he felt a pop in the knee. Though it did not hurt much then, he awoke at 4 a.m. and felt the knee throb as he turned. This time, frozen food was his salvation. Affeldt had no ice, so he applied a bag of vegetables to the knee before calling trainers.

An MRI exam confirmed the sprain, which manager Bruce Bochy said needs seven to 10 days to heal. The Giants placed Affeldt on the 15-day disabled list and purchased the contract of left-hander Travis Blackley from Triple-A Fresno. There, the 29-year-old Australian was 3-0 with an 0.39 ERA - one earned run in 23 1/3 innings - with three walks and 19 strikeouts.

Blackley made two starts for the Giants in 2007. Since then he has pitched in the minors, South Korea, Australia and Mexico.

"I've been shipped around a bit," Blackley said. "I give new meaning to the 'piece of meat' slogan they call us in the minors. It's good to be where I want to be."

Lance Iversen/The Chronicle

Joking aside, Affeldt is not happy about what happened, saying, "The trainers are tired of getting that call, 'Hey, I'm at home and I hurt myself,' " he said. "As an athlete, you'd rather get hurt doing your job than not doing it."

Briefly: Aubrey Huff took early batting practice with his teammates. Bochy expects Huff to come off the DL when eligible Monday, though that will depend on his emotional state. ... The Giants designated outfielder Tyler Graham for assignment to clear a 40-man spot for Blackley.

Giants On Deck Wednesday vs. Marlins 7:15 p.m. CSNBA Zambrano (0-2) vs. Zito (1-0) Thursday vs. Marlins 12:45 p.m. CSNBA Sanchez (1-0) vs. Vogelsong (0-1) Friday vs. Brewers 7:15 p.m. CSNBA Estrada (0-1) vs. Lincecum (2-2)