July 10, 2012

Fantasy Beat

Shields' Plummeting Groundball Rate

by Jason Collette

the archives are now free. All Baseball Prospectus Premium and Fantasy articles more than a year old are now free as a thank you to the entire Internet for making our work possible. Not a subscriber? Get exclusive content like this delivered hot to your inbox every weekday. Click here for more information on Baseball Prospectus subscriptions or use the buttons to the right to subscribe and get instant access to the best baseball content on the web.

Subscribe for $4.95 per month Recurring subscription - cancel anytime. Subscribe for $39.95 for one year a 33% savings over the monthly price! Purchase a $39.95 gift subscription a 33% savings over the monthly price! Already a subscriber? Click here and use the blue login bar to log in.

James Shields picked up in 2012 where he left off in 2011, winning five of his first six decisions while posting an ERA of 3.05.  The first month of the season even saw Shields do something better than he had ever done in the past: generate groundballs.

As good friend Tommy Rancel noted in mid-May, Shields had the third-highest groundball rate in the American League at one point, behind only Derek Lowe and Jason Hammel. In that same piece, Rancel noted that Shields was generating a high amount of groundballs in an unconventional manner. Most pitchers use sinking fastballs to generate groundballs, but Shields was getting it done using his secondary pitches. 

Shields’ rising groundball rate came at a time when the Rays’ infield was fully healthy, as the team didn’t lose Evan Longoria to injury until the final day of the month.  From that time forward, however, the defense has suffered. In fact, Joe Maddon has used seven different players at third base in Longoria’s absence: Sean Rodriguez, Jeff Keppinger, Will Rhymes, Drew Sutton, Brooks Conrad, Elliot Johnson, and even Chris Gimenez. That septet has committed 15 errors while wearing the hat of replacement level player.  Later, Matt Joyce would become injured, forcing noted defender Ben Zobrist to spend more time in the outfield rather than at second base, forcing less rangy players to field Shields’ grounders.

The effect of the replacement level defense may be playing out in how Shields is attacking hitters; his high groundball rate is now a thing of the past. Through his first 12 starts this season, Shields generated a 58 percent groundball rate. Since then, that rate has absolutely plummeted to 27 percent.

During that run, Shields has clearly changed the pitch mix from earlier this season, but the new mixture has brought less success:

James Shields 2012 Pitch Mix

Month	Four-Seamer	Two-Seamer	Cutter	Curveball	Changeup
April	18%	5%	28%	19%	30%
May	17%	6%	23%	22%	32%
June	23%	10%	18%	15%	34%
July	15%	8%	26%	18%	31%

James Shields Pre- and Post-June 1 Results

SPLIT	RECORD	IP	ERA	BABIP	StrL	StrSW	GB/FB
Pre-June 1	6-3	73	3.95	.320	19%	11%	1.5
Since	3-4	46	4.53	.361	16%	9%	1.0

The decreased use of his curveball is concerning because it was an effective pitch for him in April and May. According to his pitcher card, Shields threw 106 curveballs in April, and 18 of them were put into play. Twelve of those balls in play were groundballs, three were line drives, and three were flyballs.  In May, Shields bumped that curveball total up to 144, and of the 23 curves that were put into play, 15 of them became groundballs, two were line drives, and five were flyballs.  The first table above shows that Shields lowered his curveball rate in June, and only five of the 10 that were put into play were groundballs. Through the first two starts he has made in July, 13 of the 39 curveballs that he has thrown have been put into play, but 10 of them have become groundballs.  A pitch that was golden for Shields the first two months of season was suddenly being thrown less frequently, and when it was being thrown, the results were not as satisfactory as they had been before June 1.

It is a bit odd to see Shields bump up the use of his sinker, a pitch that his player card shows he threw just 69 times before June 1 (spanning his first 11 starts); through seven starts in June and July, he has thrown 75 sinkers.

Using the at-bat results from texasleaguers.com, we see how the change in pitch mixture has helped to change the results for hitters facing Shields:

James Shields Pre- and Post-June 1 Pitch Results

SPLIT	Pre-June 1	Since
Groundout	26%	18%
Single	17%	18%
Strikeout	23%	17%
Double	4%	7%
Flyout	7%	15%
Lineout	2%	2%
Pop-out	3%	4%
Home Run	3%	2%
Walk	7%	5%
GIDP	2%	1%
Triple	0%	1%
Error	1%	3%

The good news is that Matt Joyce should be back shortly after games resume on Friday, but Longoria could be out another month. Ben Zobrist should be spending more time at second base, though, which will help shore up part of the infield defense issues. However, the challenges on the left side of the infield that include the replacement level defenders at the hot corner and Elliot Johnson’s issues at shortstop (thus far, he’s earned a -1.2 FRAA) do not appear to be going away any time soon.

 The struggles on that side of the infield could be a reason that Shields has decreased the frequency in which he throws his curveballs to right-handed hitters.  Prior to June 1, Shields threw a total of 118 curveballs to right-handed hitters—51 in April and 67 in May. Since June 1, Shields has thrown just 43 curveballs to right-handed hitters. (Forty-two of those came in the month of June while just one has come so far in July.) Curves thrown to right-handed hitters by Shields have been put into play 27 times this season, with 15 of them becoming groundballs.

If the change in pitch mix has anything to do with Shields’ confidence (or lack thereof) in the infield playing behind him, the bad news is that the defense is not expected to get much better in the coming weeks. Zobrist should be spending more time at second base as July becomes August, but Longoria’s return to solidify the left side of the infield is as uncertain as the winning lottery numbers this weekend.

Shields had a dream season in 2011 after a nightmarish 2010, and he has shown both versions of himself so far in 2012, frustrating fantasy owners who paid a premium price for a guy that demonstrated such superior command of his craft just a year ago.

Jason Collette is an author of Baseball Prospectus. 
Click here to see Jason's other articles. You can contact Jason by clicking here