Tuesday, March 1, 2011

The Crystal Ball 2011: Chris Tillman and Jake Arrieta

With the signing of Justin Duchscherer, Chris Tillman and Jake Arrieta became linked for Spring Training 2011. With his addition Tillman and Arrieta are the most likely candidates to be sent down to Norfolk. (Although with this news, maybe not so much.)

Jeremy Guthrie, Duchscherer (if healthy) and Brian Matusz are locks for the rotation. Bergesen is probably staying...he's not great but fairly reliable. So Tillman and Arrieta are dueling for one spot.

Some point to Arrieta's September as proof that he has turned a corner and should be the front runner for the final spot in the rotation. But while the numbers are great (2-1, 2.60 ERA, 13 K, 2 BB) but it was only over 17 innings. But over the course of the season, he walked nearly as many as he struck out. Not a good recipe for a young pitcher to make a leap forward.

Speaking of the numbers...

              IP    K   BB   HR   ERA   FIP   WHIP
Arrieta     100.1  52   48    9  4.66  4.76  1.535
Tillman      53.2  31   31    9  5.87  5.89  1.528

Yeah...still doesn't look great for Tillman here.

But it seems to me that Tillman got more "swings and misses" with his stuff last season. So let's compare with the data from Fangraphs. O-Swing is swings outside the strike zone, Z-Swing is swings in the strike zone. Swing is total swing percentage, F-Strike is first pitch strikes and SWStr is swinging strikes.

           O-Swing%  Z-Swing%  Swing%  F-Strike%  SwStr%
Tillman     25.2%      66.0%   43.2%     50.0%     6.3%
Arrieta     29.0%      61.6%   43.6%     54.1%     5.7%

I thought Tillman would have had a bit more of an advantage here but they are pretty much even. Which is disappointing. I would have expected a bit more swinging strikes from Tillman's stuff than Arrieta's but up to this point, they are in a dead heat.

If I had to choose, I still like Tillman's upside better than Arrieta's but they are very similar at this point. This spring, I'd watch the strikeouts and walks for both of these guys very carefully. Homers will happen in Florida, ERAs and Wins will fluctuate with the defense but the walks and strikeouts will be the best bellwether for their competition in Sarasota. And it starts tomorrow when Tillman takes the mound against the Phillies.


Jeff said...

I wonder if Tillman's erratic control plays a role in the lack of swinging strikes. Hitters tend to be more patient and wait for something that's more of a sure thing if a pitcher tends to be erratic.

Honestly, Tillman's knuckle-curve, based on stuff alone and not control, is the best individual pitch of any of our pitchers IMO.

Ross said...

I think Tillman still has better stuff but he struggles to control it. Often he finds himself behind in counts and not in a position to garner swings and misses. I'd be curious to see the swing and miss rates when each pitcher is ahead in the count. I think you would see Tillman lead by a larger margin under those conditions. Still control is essential and Tillman won't even start to reach his ceiling until he significantly improves his control.

Heath said...

Jeff and Ross:

Since you guys both brought up the same point, I'll take the theory a bit futher...

I think Tillman lacks confidence in his stuff. Over the past two seasons, Tillman hasn't had control issues in Norfolk. He knows his stuff works down there so he throws it for strikes.

In Baltimore, I think he nibbles more (or tries to) and he get himself into trouble. You see what he can do against a good lineup when he attacked the strikezone against Texas last year. I think he just needs to trust it at this point.

Ross said...

Its really a shame we don't have pitch f/x data for Tillman's Norfolk starts. We could really test get more insight into the nibbling theory. At least we can use the pitch f/x data at the MLB level to identify any actual control improvements.