Velazquez signed a minor league contract with the Boston Red Sox on December 7, 2007, and was invited to spring training. He played the majority of the season with the team's AAA affiliate Pawtucket Red Sox, but was called up late in the season. Velazquez made his Major League debut on September 25, 2008, and played in 2 more games afterwards with one hit in eight at-bats. His hit was an RBI single to left field off of Alfredo Aceves of the New York Yankees on September 26. After Mike Lowell was placed on the disabled list in the middle of the 2008 American League Division Series, Velazquez filled his roster spot, and became eligible to play in game four of the playoffs after only three major league appearances and one major league hit, he did not appear in the series. Velazquez was invited to 2009 spring training as well after signing a new minor league contract on November 10, 2008. On April 11, 2009, he was called up to the Red Sox while Julio Lugo spent time on the disabled list. Gil was optioned back to Pawtucket when Boston called up Michael Bowden. On May 12, 2009, Velazquez was recalled to Boston when Kevin Youkilis was placed on the 15-day disabled list. Velazquez was optioned back to Pawtucket on May 20 when Kevin Youkilis was activated from the disabled list. In October 2009 Velazquez was granted free agency. He appeared in a total of six games with the Red Sox and did not record a hit. On January 15, 2010, Velazquez was re-signed by the Red Sox and again invited to spring training. He spent the entire 2010 season with Pawtucket, where he finished the season with a.249 average.
Velazquez was signed by the Los Angeles Angels of Anaheim on January 14, 2011 to a minor league contract with an invite to spring training. He was assigned to the Angels AAA Pacific Coast League affiliate, the Salt Lake Bees, on April 6, 2011 There, Velazquez was named to the 2011 PCL All-Star team. Velazquez, a 31-year-old native of Los Angeles, appeared in 123 games for the Bees in 2011, hitting a team-high and career-high.328 with 25 doubles, five triples, eight home runs, 58 RBI and 17 stolen bases. The Angels recalled Velazquez on Tuesday, September 6, 2011, during September roster expansions. Velazquez, who plays second base, third base and shortstop, made his Angels debut on September 16, 2011, pinch hitting against the Baltimore Orioles. Velazquez appeared in 3 more games in 2011. He had three hits in six at-bats.
Miami Marlins
After being granted free agency by the Angels' organization, Velazquez signed a minor league deal with the Miami Marlins, and was assigned to the AAA affiliate New Orleans Zephyrs. On August 16, Velazquez was called up to the major league team. The next day, he started in his first game for the Marlins. He finished the season batting.232 in 56 at-bats with 2 RBIs, no homers, one double and walk, in 19 games. He was outrighted off the Marlins roster on October 4, 2013 and elected free agency rather than accept a minor-league assignment.