Grabavoy played his youth soccer with the Chicago Magic Soccer Club under coach Mike Matkovich. Grabavoy attended Lincoln-Way Central High School, a large suburban Chicago school, where he played under coach Brian Papa. He led the Knights to two straight Illinois State Class AA Championship games, and as a senior, was named the 2000-01 Gatorade National High School Player of the Year. Grabavoy played three years of college soccer for the Indiana University Hoosiers. Grabavoy was a unanimous All Big-10 selection as a sophomore, and was voted an NCAA First Team All-American as a junior. Grabavoy led Indiana University to an NCAA Championship his third year.
Following his junior season, Grabavoy played for coach Mike Matkovich with the Chicago Fire Reserves in the Premier Development League, and signed a Project-40 contract with MLS, and was subsequently selected 14th overall in the 2004 MLS SuperDraft by the Los Angeles Galaxy. In his first year with the Galaxy, Grabavoy played 928 minutes, registering a goal and three assists. He added three assists in his second season, while fighting for playing time as LA won the MLS Cup and U.S. Open Cup double. In May 2006, Grabavoy was traded to the Crew in a four-player deal.
Grabavoy was selected by the San Jose Earthquakes in the 2007 MLS Expansion Draft. He was waived by the club on March 3, 2009, but was picked up by Real Salt Lake in the Waiver Draft later that same day. Grabavoy scored the winning penalty kick on November 14, 2009 at Chicago Fire to give Real Salt Lake their first conference championship and first trip to the MLS Cup final. Real Salt Lake beat Los Angeles Galaxy in the final for it first championship. He scored his first Real Salt Lake goal on May 29, 2010 against the Kansas City Wizards at Rio Tinto Stadium, the fourth goal in a 4-1 RSL victory.
In January 2012, RSL signed Grabavoy to a contract extension through the 2013 season. The following month the contract was extended an additional year through 2014.