Rafael Soriano has been a productive relief pitcher since 2003. He figures to close for the Nationals in 2013. However, he has experienced a number of arm injuries and is 33 years old. Soriano’s ERA is consistently quite low (career 153 ERA+), although there are risk factors for a drop-off in performance during his time in Washington.
- Four-seam fastball: 91–94 mph. In many respects, his best pitch. Opponents have hit .180 against it since 2007, ranking 5th out of 173 relief pitchers who’ve thrown more than 1000 four-seamers since 2007. Lateral movement is minimal, often giving it the appearance of a cutter. Has good life, as shown by high whiff/swing rate (has never been below 23%). Velocity has dropped slightly in recent years, but he figures to stay pretty close to his 2012 numbers. Thrown fairly high in the zone, which has made him a fly-ball pitcher (0.63 GB/FB since 2007, per Brooks Baseball). Typically gets above-average frequency of pop-ups. He is not afraid to pitch up and in to righties, but he avoids throwing in to lefties.
- Slider: 80–86 mph. Used nearly as often as his fastball (> 40%). Thrown to hitters from both sides of the plate, typically low and away. Especially common against lefties with 2 strikes. Even with frequent use, its whiff rate is average (≈ 30%).
- Two-seam fastball: 91–94 mph. Used exclusively on lefties, especially early in the count. He runs it off the outside corner. Has decent tailing action relative to four-seamer, but little sink. Primarily a show-me pitch.
Soriano’s strikeout totals have been good-to-great throughout his career (26% K, 9.4 K/9). His walks fluctuate, winding up near the league average overall (8% BB, 2.9 BB/9). Home run rate is also about average (0.9 HR/9). That typically creates a good pitcher but not someone whose career ERA+ is 153. In fact his career ERA (2.78) is tiny compared to his career FIP (3.30) and xFIP (3.69). He also outpaces his SIERA (3.11) and tERA (4.06).
As a fly-ball pitcher, Soriano’s xFIP is somewhat “artificially” high because his home-run rate as a percentage of fly-balls is consistently better-than-average. Still, his ability in five of the last seven years (including his four best ERAs) to significantly outperform his FIP is significant and has a probable explanation.
It turns out that Soriano has benefitted hugely from an impressive career BABIP of .249 (FanGraphs) or .251 (Baseball Reference). In his masterful 2010 season, it was just .199. (In his previous, merely respectable season, it was .280.)
The last couple of years have seen a rebound of his BABIP to .279 and then .274. If this represents a trend, Soriano’s performance in the future could suffer. Last season, he had an anomalously high LOB% of 88% (he’s typically closer to 75–80%). It’s not hard to see how a middling walk percentage suddenly becomes more dangerous if hitters are starting to make better contact. In fact, Soriano’s ERA from 2009–2012 correlates strongly with his BB% (.94) and BABIP on his fastball (.63). Strikeouts had almost no correlation.
Potential red flags
- As discussed above, Soriano relies almost entirely on two pitches, and a key to his success has been making his fastball hard to hit well. He’s very effective against right-handed hitters partly because he can pitch them inside without fear. If Soriano’s velocity continues to decline, it could spell trouble for that strategy. Being a fly-ball pitcher with a hittable fastball and occasional tendency to walk hitters would be a bad recipe for a 9th-inning guy. Soriano has thrown a changeup and cutter in the past, and if his fastball loses potency he might need to re-expand his repertoire.
- He has a long history of arm troubles, with a Tommy John operation in 2004, several DL stints for elbow inflammation, and various other maladies. His mechanics put strain on his elbow during the cocking phase, which explains the history of elbow issues. He also throws an unusually large percentage of his pitches as sliders, which is thought to be harmful to the elbow. As a 33-year-old, his body won’t heal faster than he did when he was 25 and had Tommy John surgery.
- He’s not much of a fielder, either in range or graceful handling.
For most of his career, Soriano has been a very good, albeit often overpaid relief pitcher. He has the mental fortitude to be a closer, and when he’s good he has the stuff for it. He will need to be very careful about his walk total and the effectiveness of his fastball. He is also at an above-average risk for arm injuries.
For the sake of preserving his elbow and to compensate for potential fastball velocity loss, perhaps the Nationals will encourage Soriano to rediscover his cutter or changeup.
This report was made possible due to the data at Baseball Prospectus, Baseball Reference, Brooks Baseball, and FanGraphs.