I came on here expecting to see a thread with 50 posts about this, but there wasn't even a thread at all.
To me, this is huge news.
The obvious thing is that he's our #1 LH setup guy in the 8th inning, but he also puts Cordero on a short leash. Bray, Masset or others could become that 8th inning setup guy just as easily if Cordero struggles.
I also don't think it sets anything in stone as far as Cordero being in the bullpen permanently. As hard as he throws and as young as he is, perhaps it's a good thing that he develops his arm by using it multiple times during the season for fewer innings instead of every five days for more innings. It certainly shouldn't harm him (unless Baker makes him one of the five most used pitchers in the Majors like he did Masset and Cordero last season).
There's going to be a lot of save opportunities next year, and I can't blame Walt for trying to replace Rhodes in-house with what looks to be equal talent. Let's face it. Arthur Rhodes got the job done. You don't want to go backwards there if you don't have to.