Scott Atchison has been designated for assignment to make room on the 40-man roster for free agent signing Cody Ross. Even though Ross's signing was confirmed earlier in the week, a roster crunch prohibited the deal from being finalized.
Ross will serve as the right-handed portion of a platoon in right field with another new acquisition, Ryan Sweeney. Combined, the two should make for a far superior right field than what Boston managed in 2011, as even Josh Reddick's above-average campaign at the plate couldn't make up for an team showing of .233/.299/.353, their worst line at any position.
Scott Atchison has bounced between Triple-A Pawtucket and the majors as a long-relief depth option the last two seasons. He was out of his element leverage-wise in 2010 when the bullpen was down to its last shreds of health, giving up nine homers in 60 innings while posting a 4.50 ERA. In 2011 he settled in for a solid 30 innings of low-leverage, middle relief work, with an improved 2.8 K/BB ratio and without yielding a single home run. Neither sample is particularly large, but that's because Atchison's best fit is as that kind of depth option.
There are enough arms of similar-or-better ability that losing him wouldn't be the worst thing that could happen to the roster, but, this very thing is why it's also possible Atchison will clear waivers and remain with the Red Sox, just off of their 40-man roster if/until they need him around this summer.