I think Tommy Hunter changed the math (both roster and $) for the 26. And also Irvin, who would have probably been in AAA staying stretched out, has proved his value as both a lefty reliever and an extra/tandem starter. Beyond that I think it's the $ more than the 40-man space.
Also they seem to like Kelley even though they outrighted him before. He might be the guy who gets added to the 40. I thought Swarzak may have agreed to a pay cut or a later opt-out date, but apparently not.
And yeah - for guy #29 and 30 the people on the 40 are probably good enough, especially if Howard replaces one of them (though yeah, he may be replacing Wheeler - I don't think they will start his service time if Wheeler leaves immediately). But more importantly they make minimum salary instead of $1-1.5 million.
I think Arano will work his way back eventually too.