Designated for assignment by Minnesota on Tuesday to make room for Carl Pavano, Bonser missed the 2009 season after undergoing right shoulder surgery in February.
The 28-year-old has made 96 Major League appearances (60 of them starts) since being a first-round Draft pick by the Giants in 2000. In those three seasons, all with the Twins, Bonser is 18-25 with a 5.12 ERA.
In his last full season in 2008, Bonser went 3-7 with a 5.93 ERA, striking out 97 and walking 36 in 47 games (12 starts).
Alden Gonzalez is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.