New York, NY -- (Sports Network) - Croatia's Mario Ancic will miss the U.S. Open for a third straight year, this time because of mononucleosis.

The 25th-ranked 2004 Wimbledon semifinalist missed last year's Open due to a shoulder injury, this after being sidelined for most of the year because of a bout with mono, and skipped the 2006 edition with back problems.

The 24-year-old Ancic, who owns three career singles titles on the ATP circuit, hasn't played at the U.S. Open since a second-round exit in 2005. He hasn't advanced beyond the second round there in four trips.