Bolton's American midfielder Stuart Holden has undergone another operation to repair ligaments in his right knee and will be sidelined for six to nine months.
Bolton made the announcement Tuesday, eight days after the 28-year-old lasted less than a half-hour with the Bolton under-21 team against Everton.
That was his first match since tearing his right anterior cruciate ligament during the United States' 1-0 victory over Panama in the CONCACAF Gold Cup final on July 28.
He traveled to Los Angeles and was operated on Monday by Dr. Bert Mandelbaum, the Los Angeles-based surgeon who also operated last summer.
"Unfortunately, Stuart's knee has gone. His surgeon has had a look and has deemed this to be the best course of action," Bolton manager Dougie Freedman said. "We're all obviously very disappointed for Stuart, but he's a warrior and a fighter and someone who knows exactly what he wants to achieve. Everyone at the football club is right behind him."
Holden posted a letter from a fan on his Facebook page in which a mother whose 17-year-old son tore an ACL said her son had looked to Holden as inspiration for his own recovery.
"This is why I continue to fight and never give up," Holden wrote. "An email from a fan that brought tears to my eyes and strength to my heart. No matter what obstacles are thrown in front of me, I will conquer them."
Holden's injury troubles began when he broke his right leg on a tackle by the Netherlands' Nigel de Jong during a friendly in March 2010, but he returned to make the U.S. World Cup team and appeared as a late substitute in the Americans' opener against England.
He injured his left knee against Manchester United during a tackle by Jonny Evans in March 2011, returned from surgery for a League Cup match against Aston Villa that September, then needed more surgery eight days later.
Holden came back again in January 2013 to make three substitute appearances for Bolton, four starts during a one-month loan to Sheffield Wednesday, and another short substitute stint for Bolton.
He rejoined the U.S. national team as a substitute in an exhibition against Belgium on May 29, then played extensively in the Gold Cup before getting hurt again.
In the under-21 match on March 3, Holden was in discomfort when he fell to the turf in the 23rd minute.