Cardinals first baseman Lance Berkman will undergo additional surgery on his right knee Friday morning, effectively ending his season and further focusing him on possible retirement.

Berkman underwent his second magnetic resonance imaging in less than three weeks Monday. A determination was made that he requires additional meniscus shaved from a knee that already has required three surgeries, including one this May after the joint gave way during the team's first trip to Los Angeles.

Berkman eventually returned, only to take a Clayton Kershaw pitch off the same knee during the teams' late July series at Busch Stadium.