Here's a Thought: MLB's 10 Most Effective Splitters

Based on the success of my "MLB's 10 Most Effective Curveballs" and "MLB's 10 Most Effective Sliders" articles, I decided to look at the 10 most effective splitters this season.

I'm measuring splitter effectiveness by Pitch Type Linear Weights, which says how many runs a pitcher prevents above average every time he throws 100 pitches.

So, if I say a splitter's effectiveness is one run above average, that means that every 100 splitters that pitcher throws, he allows one run less than average.

I set two ground rules. First of all, pitchers have to have thrown at least 25 innings this year. Second, they have to use the splitter at least 10 percent of the time.

For each pitcher, I'll list the average splitter velocity, average splitter movement relative to an average major league fastball (if you want to know why I'm comparing it to a fastball, just ask), splitter usage (how often the pitcher throws the splitter), and splitter effectiveness (as measured by Pitch Type Linear Weights).

Also, just to clarify, this is me taking the leaderboard on splitter effectiveness, listing the top 10 pitchers, and analyzing their splitter's success. This is NOT a subjective list. So don't tell me I'm "leaving somebody off." It's just the leaders in the stat and my analysis for why they're leading.

Let's take a look.

10. Danys Baez

Splitter Effectiveness: 0.57 runs above average
Splitter Usage: 28.9%
Splitter Velocity: 89.9 mph
Splitter Movement: 2.0 inches right to left, 4.2 inches down

Because fewer pitchers throw splitters than sliders, curves, or changeups, you can see that the value of the 10th-best splitter is much lower than the 10th-best version of those other pitches.

After missing all of 2008 with arm problems, Baez has returned this season throwing his splitter about five times more often than before.

It has some cutting action to it with a fair amount of drop.

Since Baez is throwing the pitch far more often than he ever has, batters are perhaps being slow to adjust to his new splitter-heavy style.

9. Braden Looper

Splitter Effectiveness: 0.57 runs above average
Splitter Usage: 33.6%
Splitter Velocity: 82.5 mph
Splitter Movement: 0.6 inches left to right, 6.2 inches down

Looper throws a lot of splitters, and the pitch has excellent late drop, allowing it to be effective in spite of its heavy usage.

8. Brian Sanches

Splitter Effectiveness: 0.73 runs above average
Splitter Usage: 14.3%
Splitter Velocity: 80.0 mph
Splitter Movement: 0.4 inches right to left, 5.5 inches down

Sanches, long a favorite of mine, has finally found major league success this year (0.95 ERA), and his splitter has been a big part of that success. It has a big velocity separation from his fastball and features above-average late drop.

Sanches' splitter has finally become a big out pitch for the Marlins' righty.

7. Kenshin Kawakami

Splitter Effectiveness: 1.14 runs above average
Splitter Usage: 17.0%
Splitter Velocity: 84.7 mph
Splitter Movement: 1.4 inches left to right, 5.1 inches down

The splitter/forkball is a popular pitch over in Japan, and Kawakami's countryman Koji Uehara boasts the 11th-best splitter in the majors.

Kawakami's splitter has nice late fade and above-average drop, and it's made even more effective by his array of other pitches that set it up.

6. Carlos Zambrano

Splitter Effectiveness: 1.28 runs above average
Splitter Usage: 13.9%
Splitter Velocity: 84.5 mph
Splitter Movement: 1.2 inches right to left, 7.2 inches down

Zambrano throws a very heavy splitter with a ton of late drop. He's only started heavily using the pitch this season, and it's helped him a lot.

The pitch also has some cutting action into lefties and away from righties, further enhancing its effectiveness.

5. Jose Valverde

Splitter Effectiveness: 1.48 runs above average
Splitter Usage: 27.8%
Splitter Velocity: 85.0 mph
Splitter Movement: 1.3 inches left to right, 7.7 inches down

Valverde has good velocity and extreme drop on his splitter, and it's no surprise the pitch has met with success. He uses it as his main offspeed pitch to complement his mid-90's heater.

4. Ed Mujica

Splitter Effectiveness: 2.13 runs above average
Splitter Usage: 16.0%
Splitter Velocity: 87.2 mph
Splitter Movement: 1.2 inches right to left, 6.6 inches down

One of a seemingly never-ending string of unheralded pitchers to do good bullpen work for San Diego this year, Mujica has an excellent fastball-slider-splitter combo. His slider has rated even better than the split this year.

Like many pitchers on this list, Mujica throws a splitter with a little cut into lefties and a lot of late drop. Because he has the good fastball and slider to back it up, Mujica's splitter is far more effective than those of the six pitchers behind him on this list.

3. Dan Haren

Splitter Effectiveness: 2.46 runs above average
Splitter Usage: 13.3%
Splitter Velocity: 85.2 mph
Splitter Movement: 2.8 inches right to left, 4.2 inches down

Haren's splitter is perhaps the best-known splitter in baseball, and its effectiveness (best among all starting pitchers) certainly justifies this.

Haren's split has just average drop, but it has a ton of cutting action, neutralizing lefties and righties alike.

He uses it almost exclusively in two-strike counts as a chase pitch in the dirt, and batters simply can't lay off the pitch.

2. J.J. Putz

Splitter Effectiveness: 4.57 runs above average
Splitter Usage: 14.6%
Splitter Velocity: 85.3 mph
Splitter Movement: 0.1 inches right to left, 6.3 inches down

Putz's hard splitter basically drops straight down, and hitters are usually too concerned with his mid-90's explosive fastball to pick the splitter up...until it's too late.

Like Haren, Putz uses the splitter as an in-the-dirt chase pitch to finish batters off.

1. Frank Francisco

Splitter Effectiveness: 5.38 runs above average
Splitter Usage: 18.3%
Splitter Velocity: 85.5 mph
Splitter Movement: 0.4 inches right to left, 2.7 inches down

Oddly, the best splitter on the list is the one that moves the least.

Two things make Francisco's splitter more effective. First, he has a mid-90's fastball and hard curve to set it up.

Second, the fastball has less sink than most do, so while Francisco's splitter only sinks 2.7 inches relative to a normal fastball, it sinks 5.2 inches relative to HIS fastball. The difference in movement between his fastball and splitter is fairly large, making up for the lack of movement in the splitter itself.

Francisco's splitter is having by far its most effective season, and it will be interesting to see if he can continue to succeed with it. If he can, he'll move to elite closer status in short order.