Yes, Lincecum was not top 10 last year, possibly not even making top 15 (and I am a big Lincecum fan) but he was so dominant for the three 2008-2010 seasons... a high rating is probably warranted based on those years, maybe not 99 though
wudl is completely right in the regard that ERA depends so much on fielding that it is a poor stat to judge pitchers by, and it is very tough to come to a conclusion regarding this season after only 3 starts.
his drop in velocity is particularly troubling though, and I hope he can recover, otherwise I feel pretty bad for him. He has apparently dropped his slider as well, maybe due to the mechanical stress it puts on a pitchers arm? Who knows...