An Examination of Knuckleballer Steven Wright

Knuckleballer Steven Wright spent six years in the minors before cracking a major-league roster in 2013, at the age of 28. However, it wasn’t until 2015 that he was treated as more than emergency filler, appearing in 16 games (9 as a starter) with a 4.09 ERA (106 ERA+). In 2016, as a regular starter, he was one of Boston’s best pitchers before a shoulder injury in the first week of August sent him to the disabled list for the rest of the year. Before his injury, Wright put up a 3.33 ERA (137 ERA+) and a 1.245 WHIP in 156 ⅔ innings, with a 13-6 won-lost record.

What he throws. Wright’s main pitch is, of course, the knuckleball (“KN”), a pitch he started using in 2010 after several years of futility in the minor leagues. As well as the knuckler, Wright throws two different fastballs – a four-seam fastball (“FF”), with an average velocity of 86.5 mph, and a sinker (also called a two-seam fastball (“FT”), averaging 83.1 mph and with more horizontal movement than the four-seam version. He also throws a curve (“CU”) averaging 66.5 mph; his knuckleballs occasionally spill into the range of movement and velocity of his curves, so there is some uncertainty about identifying these pitches:

Trends. Wright only reached the majors because of his knuckleball, and unsurprisingly it is by far his most common pitch (79.0% of pitches). His sinker and curve are his next most frequently used pitches (10.6% and 6.6%, respectively), with his four-seam fastball only being deployed about 3.8% of the time. Wright uses his knuckleball equally to right- and left-handed batters. When behind in the count, he tends to use the knuckleball less, switching to his sinker instead; for example, the 26 times he reached a 3-0 counts, he used his sinker 23 times, only going to the knuckler three times:

His pitch usage didn’t change much over the season, although most of his four-seam usage was during a handful of games in June and July:

Pitch value. Wright’s knuckleball is more effective than the average knuckleball, giving up 7.5 total bases per 100 pitches compared to the average of 9.3 TB/100. That doesn’t say much since just two pitchers threw over 95% of the 4306 knuckleballs identified in the major leagues in 2016; that just says that Wright’s knuckleball was more effective than R.A. Dickey’s. However, knuckleballs overall were actually quite effective, based on total bases yielded per 100 pitches – for comparison, the average fastball yielded 9.8 TB/100 – making Wright’s knuckleball well above the overall average pitch. Knuckleballs are notoriously difficult to locate, but Wright’s rate of balls per 100 pitches was in line with both the average knuckleball, and with major-league pitches overall (38.8% B/100 for Wright’s knuckleball; 36.0% for all pitches).

None of Wright’s other pitches were as effective as his knuckleball by TB/100, although his sinker, to left-handed batters, was slightly better than the average knuckler (7.2 TB/100). His sinker was excellent at hitting the strike zone, explaining why he turned to it when behind in the count. His four-seam fastball was about average to left-handed batters but very bad against right-handed batters, while his curve was worse than average against both, and also had a very high rate of balls against righties:

Pitch location: After Wright releases the knuckleball, he has no more idea where it will go than the batter does. It ends up averaging more or less in the middle of the strike zone, but with a broad smear of locations covering the whole zone. His sinker also targets the middle of the zone, with a tighter distribution, while his four-seam fastball tends to be inside to left-handed batters – often very far inside – and outside, or high, to RHB. His curve seems to have two main destinations, either high and outside to lefties (high and inside to right-handed batters) or low and inside to lefties/low and outside (often falling well outside the strike zone) to RHB; he prefers the former to lefties and the latter to righties:

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Featured image courtesy of Maddie Meyer.