Dodgers reliever Javy Guerra was placed on the disabled list with a knee injury Monday, but the extent wasn't yet known. It is now. Guerra had to undergo arthroscopic surgery on his right knee and is expected to miss four to six weeks (latimes.com).

Guerra actually injured the knee back on April 28, according to the LA Times. Since then he has been pitching through the pain without fully disclosing it to the team. He finally realized the pain was affecting his mechanics, which is why he left the team Sunday to have his knee examined.

Guerra, 26, opened the season as the Dodgers' closer but has since lost that job to Kenley Jansen. Guerra has a 3.38 ERA, 1.50 WHIP and 20 strikeouts in 24 innings. His ERA is actually 1.32 since April 28, so it's not like the injury ruined his numbers.

The Dodgers have Josh Lindblom -- who has been great -- and Ronald Belisario as set up options.

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