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How Luck Can Shape Perception: What Has Gone Right For Tampa Bay's James Shields

James Shields has looked awesome so far in 2011, but is he really a new man, or just a lucky mirage?

There are 10 kinds of people in the world: Those who understand binary, and those who don’t. In my experience there are also two kinds of Rays fans: Those who hated James Shields last season, and those who simply thought he was unlucky.

Shields is off to a phenomenal start to the 2011 campaign: His ERA is 2.35; his walks are down; and he’s just looking dominant. Two complete games in a row can have that effect. So, is he really pitching that much better than in his forgettable 2010, or has he just been getting luckier?

The thing we can definitively say is that Shields is getting way luckier. Look at his batting average on balls in playleft on base percentage, and home runs per fly ball compared to years past.


















These statistics are the three things to check when looking at a pitcher’s luck. Bradley Woodrum did a much more detailed and entertaining job of explaining it (in the links above), so be sure to check out those videos if you aren’t already familiar with the stats.

What we’re seeing here is that for all three statistics, Shields’ 2010 was very bad; his 2011 (so far) has been very good, with his career numbers almost smack-dab in the middle. BABIP, LOB%, and HR/FB are the factors that a pitcher has minimal control over and tend to stabilize around the pitcher’s career norms over the course of a season. His bad luck last season made him look like a bum, and his fortune now makes him look like a beast.

I am not enough of an expert in pitch usage to say whether James Shields has done anything to alter his numbers or improve his results. He has a devastating changeup and his curveball has looked outstanding, to complement a fastball that has maintained the increased velocity we saw last season (average 4-seam fastball velocity of 91.5 mph both years). What I can say is that Shields is walking fewer than 2 batters every nine innings and that he is striking out nearly two batters fewer as well.














The decrease in strikeouts may look concerning, but not to me. I see James Shields as a complete pitcher, one who is willing to sacrifice greater strikeout numbers to play to his defense and, in the process, go deeper in games. He clearly still has the ability to strike guys out when he needs to, and I personally would rather see him pitch deep into games to the tune of a few less strikeouts.

What all of the numbers are saying is that James Shields is who he always has been. He’s looking like an ace right now, but don’t be fooled. He has been as lucky this season as he wasn’t last year. In all likelihood he will return to his career averages and be very, very good (but not great). 

Photographs by, thelastminute, turtlemom nancy , fesek, kthypryn, justinwright, sue_elias, pointnshoot, and scrapstothefuture used in background montage under Creative Commons. Thank you.