MIAMI • Cardinals third baseman David Freese underwent reconstructive surgery on his right ankle Thursday in Vail, Col., according to a source familiar with the situation.

The procedure involved reattaching a tendon to his ankle, which suffered extensive damage as Freese was on a minor-league rehab assignment Monday in Springfield, Mo.

Freese, who first hurt his ankle when he stubbed his foot at third base on June 5 in St. Louis, had been on the 15-day disabled list with a bone bruise on his ankle, and was playing in his first rehabilitation game at Springfield when he got hurt rounding third base.

Thursday's procedure, performed by Dr. Thomas Clanton at the Steadman Clinic, will require at least six months of rehabilitation, according to the source.

Freese's availability for the beginning of next spring training is uncertain.

Team officials Tuesday said Freese would require surgery but offered no time frame. Freese, who was not at Busch Stadium the day after he was hurt in Springfield, traveled to Colorado on Wednesday before undergoing Thursday's procedure. He remains in Colorado with his father, according to a source familiar with the situation.

Thursday's surgery was described as extremely serious as tendon had to be reattached to bone.

The Cardinals continue to search for short-term help at third base but the prognosis, not yet announced by the team, increases the likelihood that they will have to find help at the position for next season as well.

In 2009, Freese missed much of the season with a left ankle injury. He finished this season hitting .296 with four homers and 36 runs batted in.