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Chris Tillman's got a brand new bag, or at least a new sinker

Chris Tillman has been off to a great start in July. One of the reasons for his success has been an increasing ground ball rate fueled by the use of a new sinker. This new pitch has been a weapon for Tillman so far in the second half.

Tommy Gilligan-USA TODAY Sports

Chris Tillman has always been an enigmatic starter. Running low strike out rates and mediocre walk rates while still producing shiny ERA's. He has accomplished this through running a low BABIP, a high left on base rate(LOB%), holding runners extremely well, and inducing a high rate of infield fly balls. This is a fine line to work when you are a pitcher. If your command sinks, all of these peripheral statistics can go south and your ERA with them.

In the first three months of 2015, this was Chris Tillman. He had poor command which led to more walks, more contact, and harder contact . His BABIP was way higher than his career levels and his LOB% cratered which in turn created an abundant ERA. This led some to think that maybe the rose had finally lost it's bloom on Chris Tillman. That his peripheral statistics may have been produced more by random chance than by true talent. Well, Tillman has come out roaring in July.

Splits ERA FIP BABIP IFFB% GB%
April to June 5.67 4.75 .306 16.8% 39.2%
July 1.31 2.30 .253 14.3% 53.6%
Career 4.05 4.44 .275 10.6% 39.4%

The table above is split into three time periods. First is from April to June of the 2015 season, next includes all of Tillman's starts in July, and lastly are his career numbers for some context. Of note, his IFFB% is actually way up this year, which may just be a yearly fluctuation and even so it did not help him from April to June. He ran a high ERA, high BABIP, and right around a career ground ball rate. Not to mention a walk rate of 10.4% compared to a career 8.4%.

However, in five July starts, Tillman's ground ball rate has gone way up. Ground balls are a pitcher friendly outcome for many reasons. A ground ball can never be hit for a home run and barely ever goes for extra bases. Furthermore, a ground ball in 2015 has been recorded for an out 76 percent of the time. If a pitcher is going to let up contact, a ground ball is about the best they can do.

As you can see, for his career, Tillman has not been a ground ball pitcher. He often ranks near the bottom each year in GB%. He makes up for this by inducing soft contact on his fly balls and inducing an above average rate of infield fly balls, which are outs nearly 100 percent of the time.

Yet, in July, Tillman has been getting grounders and still maintaining his IFFB%. This may simply be a fluctuation. This is only a five start sample size compared to his career of 138 starts. But, I had noticed that Tillman seemed to be throwing a different fast ball of late. So I went and looked at his pitch f/x data and sure enough, according to Brooks Baseball, Chris Tillman has been mixing in a sinker as of late.

2015 Month SI% FB% CT% CU% SL% CH%
April 2.2% 63.0% 10.7% 13.0% 0.3% 10.8%
May 3.8% 59.4% 7.7% 16.4% 0% 12.8%
June 8.4% 62.0% 2.2% 15.9% 0% 11.5%
July 17.3% 46.7% 5.8% 14.31% 1.0% 14.9%

The usage rate of his sinker has gone through the roof in July. For the total of 2015 his sinker usage rate is currently 8.2 percent and climbing, before 2015, his sinker rate was never higher than 1.8 percent in a year and last season it was less than 1 percent. Sometimes, PitchF/x can mislabel a pitch based on the data.

That's why a slider will show up from time to time in Tillman's pitch usage when it's really just his cutter that had more slider like attributes than his previous cutters. Same could go for this, but with such a high usage rate it does not seem like a mistake. This is certainly seems to be a new pitch for Chris Tillman and a very new one at that.

In 2015, Tillman's sinker has about two more inches of vertical drop than his four seam fastball and about three more inches of horizontal movement. Not to mention that Tillman has been locating the sinker about a half a foot lower than his four seam fastball. All of this is simply a new weapon, a new way to approach hitters and get those ground balls which Tillman had struggled to get for the majority of his career.

In 2015, for every sinker put into play off of Tillman, two thirds of them are ground balls. The only one of his pitches that is producing ground balls more frequently is his curve ball. Meanwhile, his four seam fastball only induces a grounder about a third of the time it is put into play.

Chris Tillman is the Orioles defacto ace. He has been on the team consistently for four seasons now and while being inconsistent from start to start has shown a track record of health and good results. To begin 2015, Tillman struggled and it appeared that his poor peripherals may have been catching up to him at last. Yet, in the month of July Tillman turned his season around.

This could be because of random fluctuations and regressions, but Tillman has started utilizing a new pitch, a sinker. That sinker has been a ground ball machine and has given back Tillman the results he had been used to. Whether or not this continues to be a trend remains to be seen. This could be anything from bad data to a small five start sample where Tillman is messing with a new grip. But, the results have been encouraging. If Tillman can keep this up, he may have reinvented himself.