If you're in a keeper league, I wouldn't drop any of those three guys for Schmidt if you're only going to stash him.
If you're playing only for this year, yes, I'd drop him for Broxton. I think Lincecum is going to be a stud once he arrives on the scene this year.
Schmidt had velocity problems coming into last season and kinda ironed them out and had a , while inconsistent, a fairly good year last yeat.
I'm going to hold onto him on the DL and then I will ONLY spot start him for the rest of his career, unless he starts compiling 15 K games again. I think that part of his career is over though.