MANCHESTER, England (AP) -- Manchester United midfielder Owen Hargreaves will miss the start of next season after another setback following a series of knee problems.

Hargreaves made one brief substitute appearance in May to end a 19-month absence from the game, during which time he had surgery on both knees to treat persistent tendinitis.

But United manager Alex Ferguson said on Thursday that "Hargreaves is back in America seeing a specialist. He will not be ready for the start of the season. I do not know when he will be back.''

The 29-year-old Hargreaves has been plagued by injuries since signing from Bayern Munich in July 2007.

The new season begins in August.

SI Apps
We've Got Apps Too
Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide - from Peter King, Tom Verducci, Lee Jenkins, Seth Davis, and more - delivered straight to you, along with up-to-the-minute news and live scores.