It's obvious Bloom has reserved a place for Weber on the 26 man roster.
I think a big reason is he is at best a marginal talent. He pitches to contact and gives up a lot of hits that don't leave the ballpark, so his peripherals do outperform his performance, but really, he needs an elite defense behind him to be effective and the Sox simply do not have one.
He has only had an ERA below 5 once in his career in a season with more than 4 IP, and even then it was a 4.76.
As he turns 30 this year, he is not ikely to suddenly morph into anything better, whereas younger pitchers like Lakins, Poyner and Reyes did at least have a chance to improve....