The Boston Red Sox sent right-handed reliever Mark Melancon to Triple-A Pawtucket on Wednesday.

Melancon, who was acquired as part of a three-player trade with the Astros in December, allowed six runs on four hits -- three homers -- and two walks without retiring a batter Tuesday against the Rangers.

He has posted a 49.50 earned run average in four appearances this season after recording a 2.78 ERA in 71 games with Houston in 2011.

The Red Sox recalled Japanese right-hander Junichi Tazawa from Pawtucket to fill the vacated roster spot. Tazawa spent most of last season in the minors after undergoing Tommy John surgery in 2010.