Sure, he throws the fastball more than his other pitches. Every pitcher does. He has three other pitches, though, all of which are supposed to be average to plus. Even from the first section of the article (linked above):

The beauty of Soria is not the fastball, which he throws consistently for strikes, but his off-speed and breaking stuff. His change-up (84 mph) sinks and tails, his slider really slides (79) with a lot of horizontal movement and his overhand curveball is a big breaker, floating in at just over 69 mph.

And the fact that there were only 2 closers of his caliber to make transitions screams the key phrase for this site: “small sample size.” The fact that only two elite closers have done it only proves that very few managers/organizations have tried it. And that piece of data does not prove that it’s a bad idea. Baseball managers/organizations make bad decisions all the time. This guy went to all of this effort and didn’t follow his own data that said making him a starter is worth a shot. Instead, he jumped right back onto the contemporary bandwagon and said don’t do it despite the data I’ve provided. Someone needs to rock the boat.

I’m not saying it’s obvious that Soria should be starting. (I want him to, though.) I’m saying his data does not match his conclusions.

But, man if it doesn’t come up every few weeks somewhere. What surprised me was how few comps I could find. It just seems that guys will go from starter to closer to starter, from reliever to starter, but not closer to starter. Not many guys come in in that role, so that limits the field.

I think the group is self selecting. Guys with potential starter stuff that are actually more valuable/reliable as closers probably share some characteristics (good enough stuff, not good enough stamina/health) that keep them in the job.

*added

although I just use (1+LI)/2.

For a pre-Rally’s pitchign DB historical war application (including Soria’s last two season), click here. I used FIP, which I think is preferable for relievers anyway, and got Soria at 3.3 in 2007, and 2.3 in 2008. He was used better in 2007 when he spent part of the season as a setup man… I want to use deLI and do a study of how often setup men get higher WARs than starters in recent seasons, and how many times they deserved it or the manager was just too dogmatic about usage.

Again, this all depends on how good you think Soria can be as a starter. Which is why I appreciate the stuff you’re doing — it gets addresses the issue straight on. We need to deal with the scouting and Pitch f/x angle because multiple times through the order, diifferent pitches, etc. make a difference.

Still, let’s take the standard view that reliever —> starter = +1 FIP or RA or whatever. Plugging into my WAR-generator spreadsheet (it need to be updated a bit, but whatever) and assuming last year’s AL run environment, .370 replacement level, pythagenpat, etc.. CHONE projects Soria’s FIP as 3.04. As a starter, then, we’ll make it 4.04. 30 starts, 200 innings = 3.4 WAR. Now, I don’t know if he could do that. Certainly not this season, as that’s a dramatic increase in innings. But the point is how he would be most valuable. I seriously doubt he’s going to be worth 3.4 WAR this season, even if he hadn’t gotten injured.

Again, I’m not saying this “disproves” your piece, which goes at it from another, and important, angle. But I don’t think any reliever in baseball (except maybe Rivera) was worth that much last season, although I’d have to look again.