Each week, the Rookie Report takes a look at the most prominent recent additions to major-league rosters, as well as players who recently made their debuts.
Boof Bonser, SP, Twins: The next rookie pitcher to make his major-league debut, Bonser will replace Kyle Lohse in the Minnesota rotation beginning on Sunday. If his name sounds familiar, it should; he was one of the three pitchers the Twins acquired from the San Francisco Giants in the A.J. Pierzynski trade in Nov. 2003 (Joe Nathan and Francisco Liriano were the others). At the time, Bonser was considered a hotter prospect than Liriano was, though as he reached the higher minor-league levels, Bonser's stuff wasn't quite so extraordinary, he became more homer-prone and he seemed to get distracted at times. Still, the kid does have a 27-20 record, 3.83 ERA, 1.307 WHIP and 8.9 strikeouts per nine innings ratio in 64 starts since joining the Twins' organization, all in Double- and Triple-A ball, so it's not like he's washed up, either. Bonser, who legally changed his name from John to "Boof" in 2001, does have back-of-the-rotation potential in the long term, and in AL-only leagues, he's as worthy of stashing away as any rookie starter. His 4.1 walks-per-nine ratio in his minor-league career does suggest he's not as polished a pitcher for this year as Scott Baker, but Bonser could develop quickly enough to be a useful matchups option, perhaps a bit higher-risk version of Baker with a handful more K's.