Breaking Down James Shields

What a difference a season can make. For a pitcher like James Shields, considered the ace of the Tampa Bay Rays, this statement has borne itself out over the past couple of seasons.

In 2010, Shields had a miserable season. Even though he managed a 13-15 record, he had an ERA of 5.18, and led the American League in hits allowed with 246 over his 203.1 innings pitched. Shields also led the league in earned runs and home runs allowed, with 117 and 34, respectively. Meanwhile, he only walked 51 batters, while striking out 187, good for a 3.67 K/BB ratio.

Delving deeper into the 2010 season, Shields was the victim of some bad luck. He had a batting average against on balls in play of .341, far above the average of .297. In part, this was due to career highs in line drive rate, with 22% of balls put in play, and a 10% home run to fly ball rate. However, with even neutral luck, Shields managed an xFIP of 3.55, indicating that he was far better than his ERA showed.

Everything came together for Shields in 2011. Despite a record of only 16-12, Shields finished third in ERA at 2.82, and led the American League in complete games (11) and shutouts (4). Over the 249.1 innings he pitched, Shields only permitted 195 hits, walking 65 batters while striking out 225. Shields made his first All-Star team, and finished third in the AL Cy Young voting.

While his K/BB ratio dropped to 3.46, the rest of Shields’ underlying rates decreased. His line drive rate decreased to 17%, and his home run to fly ball rate decreased to 8.5%. This helped lead to a major decrease in batting average against on balls in play, as Shields ended the season at .258, far below the major league average of .295. Yet, Shields was not considered to be overly lucky, as his xFIP of 3.25 was fairly close to his actual results.

This season, Shields is 8-5 with an ERA of 4.17 in what is generally considered a down year. While Shields has given up a league leading 135 hits in his 118.2 innings pitched, the majority of his rates are similar to 2011. His line drive rate is exactly the same at 17%, and his home run to fly ball ratio has increased slightly, rising to 9.3%. Meanwhile, his groundball to fly ball ratio has had the greatest improvement. Last year, Shields had a GB/FB rate of 0.85; this year, that rate is at 1.20. However, perhaps in part to the Rays’ defensive issues this season, his batting average against on balls in play has jumped to .335. This is further evident in Shields’ xFIP, which is at 3.44 thus far.

While regression may have been expected from his phenomenal 2011 season, James Shields has not been as bad as perceived this season. Shields simply appears to have been a victim of bad luck at this point of the season.