One of my greatest fears about Brandon Morrow's planned move to the starting rotation is that leaving the bullpen and getting stretched out will take a few miles off his seemingly unhittable fastball. This is par for the course - relievers are able to go max-effort on every pitch, meaning they throw a little harder than they do as starters. Even Jorge Campillo was clipping 88-89 in short work. It's been several weeks now that I've been preoccupied with concerns about what Morrow would look like throwing 94-95 instead of 97-98; needless to say, I haven't been very optimistic.

Well, recently I decided to go into the Enhanced Gameday numbers to see if my fears are legitimate. I can't give enough thanks to Matthew (Carruth) for compiling the raw data - this would've taken forever to put together myself. Thanks to Matthew, I have Gameday velocity and result data for 818 of Morrow's 1193 pitches thrown this year. It's not all of them, but I believe it to be a meaningful and representative sample.

After subtracting 2mph off of every pitch Morrow threw in Safeco (Dave and I believe that home velocities were slightly inflated), I split Morrow's pitches up into three groups...

96mph or more: the "unhittable" heaters
90-96mph: the get-me-over slower fastball
Under 90mph: mostly offspeed stuff

...and looked at the relevant results. Here's a table:

The category headers, from left to right, are number of pitches, strike percentage, called strike percentage, swinging strike percentage, foul strike percentage, in-play strike percentage, groundball percentage, flyball percentage, line drive percentage, infield fly percentage, total balls in play, height in strike zone on Gameday, and overall frequency.

First, the good news - based on 2007 data, Brandon Morrow's "slower" fastball is every bit as difficult to hit as his "fast" one. In fact, it was actually put in play a little less often. While the data sample is still smaller than I would've liked, it would appear that my fears were unwarranted, and that Morrow has a good fastball whether it's going 94 or 98. Keep in mind that the league-average swinging strike percentage is 14%.

Now the bad news. To start with, Morrow doesn't throw strikes. His "slow" fastball - the one he'll presumably be working with in 2008 - had a 60.9% strike rate, against a league-average of 63%. On top of that, his fastball gets hit in the air all the time. Don't be thrown by the 42.1% groundball rate for 96+ mph fastballs; the sample is tiny. For all pitches of 90mph or above, Morrow allowed twice as many flyballs as groundballs. It's one thing to be flyball-friendly, but this is absurd. Morrow should take Safeco out to dinner.

For more bad news, look at the <90 category. Less than a quarter of Morrow's recorded pitches were "offspeed", and nearly half the time they missed the zone. Now, granted, I don't have data for everyone in the league, but I'm guessing that a 53.5% strike rate for breaking balls is hilariously bad. They weren't even particularly effective, either, with a 13% swinging strike percentage. Morrow's offspeed stuff does not appear to have been all that good in 2007, which means he's going to have to get a lot better over the offseason if he wants to survive as a starter. Nobody lasts real long with a good but wild fastball and wilder secondary stuff.

On the plus side, look at the in-play results. Again, 33 balls in play is a really small sample, but on offspeed pitches Morrow allowed 16 grounders and 7 flyballs. GB/FB numbers tend to stabilize really quick, so I don't think this is a simple anomaly. It looks like Morrow can really keep the ball on the ground fairly often when he puts some spin on the ball. It isn't the location of the pitch - you'll see his offspeed stuff ends up at the same height as his fastballs - but the downward movement. This is going to be key if Morrow wants to give his outfield a break and maybe get a few double plays.

I'll admit right now that I don't think we can safely draw any 100% clear conclusions from this. No matter how you break the numbers down, switching from the bullpen to the rotation is a huge change, and Morrow has the entire offseason to develop his skillset. That said, I do think there's some interesting substance to this. When he gets it over, Morrow's fastball is good, no matter how fast or slow it is. The flyballs come from his heaters. His secondary stuff needs a ton of work, but has potential to be the groundball weapon he needs in order to become more efficient. It really gives you a glimpse into what Morrow will have to work on this winter. I don't think he's as close to becoming an impact starter as some other people do, but at least I can be pretty certain that no matter how he does, he'll be missing some bats. After what we saw from the starters in 2007, that's something of a breath of fresh air.