San Diego Chargers wide receiver Danario Alexander recently had a second anterior cruciate ligament surgery to repair damage to his right knee, according to the San Diego Union-Tribune.

Alexander had to have the surgery in January following a reconstruction procedure in August when he first was injured.

Alexander has a lengthy history of problems with his knee.

He's a pending unrestricted free agent who caught 37 passes for 658 yards and seven touchdowns in 2012.

For his career, Alexander has 83 catches for 1,395 yards and 10 touchdowns.

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Aaron Wilson covers the Ravens for The Baltimore Sun.