Michael Fulmer's changeup helped him have an historic rookie year

Rookie righthander Michael Fulmer was the hero the Detroit Tigers needed in 2016, not the one it deserved. Acquired at the 2015 trade deadline along with young righty Luis Cessa (who was later dealt to New York in a package deal for Justin Wilson during the offseason), Fulmer often came up bigger than many, if not all of us Tigers fans expected.

That is a lot to ask of a rookie, especially when you realize the Tigers did not plan for him to pitch this many innings at the major league level through the season. This article aims to dive into what exactly was behind his successful rookie campaign and how successful it actually was.

Fulmer was the mercury fulminate of the Tigers' pitching staff, and the entire team, really. In case you haven't brushed up on your chemistry, or haven’t seen Breaking Bad in a while, here’s a refresher.

We knew we would see a few MLB starts from Fulmer at some point in 2016, whether it be due to injury, poor performance by another starter, or any other oddity that occurs during a baseball season. We didn’t have to wait long to see him, though.

With a preseason injury hobbling Daniel Norris and Shane Greene headed to the disabled list, Fulmer was called up at the end of April. He made his first major league start on April 29 against the Minnesota Twins, and allowed two earned runs on seven hits with a walk and four strikeouts in five innings.

He had a few rough starts after that, but sorted things out quickly before going on a 33 1/3 inning scoreless streak, a Tigers rookie record. Fulmer fell just 1 2/3 innings short of the major league rookie record of 35 innings set by Fernando Valenzuela in 1981. Fulmer logged four consecutive scoreless outings during that streak against Oakland, the Los Angeles Angels, Toronto, and the New York Yankees.

Fulmer's season and dominate scoreless streak were due in part to his newfound success with his changeup, which he used a maximum 9.78 percent of the time in his first four starts. From then on, he used it anywhere from 11.36 percent to 29.47 percent of the time.

In fact, the only start in which he used his changeup less than 11 percent of the time the rest of the season was his last start, a 3 1/3 inning outing shortened due to a combination of a rain delay and Fulmer's struggles against the Cleveland Indians.

Fulmer touched on his changeup in an interview with FanGraphs.

"I honestly have no idea why it got good. I basically threw it in a bullpen session until I it got right, and ever since then I’ve been keeping it down and getting good action on it. I threw about 30 in a row that day — it was at Comerica Park on either May 18 or 19 — and John [Murrian], our bullpen catcher, was like, ‘Where did that changeup come from?’ I was like, ‘I don’t know; I just kind of threw it.’ He said it’s the best it’s been, and it’s pretty much stayed that way."

Fulmer’s changeup ended up being his single best pitch of the season. It ranked sixth in pitch value among all pitchers who pitched at least 150 innings in 2016. When weighted per 100 pitches it ranked fifth among all major league starters and second in the American League.

In total, Fulmer threw 433 changeups out of 2,467 total pitches, a 17.55 percent usage rate. He faced 647 batters in the season and used the changeup in 96 different at-bats, which equates to about 14.84 percent of the batters he faced. His average velocity on the changeup was 86.5 miles per hour.

Combine that with his average extension of 6 feet, 2 inches when throwing a changeup, and you get an average perceived velocity of 86.64 mph. The average spin rate on his changeup was 1,730 rpm, which was about dead-even with the league average spin rate on all changeups thrown.

When batters did make contact with Fulmer’s changeup, which was pretty rare, the average exit speed was 90.2 miles per hour. That is only about 3.5 mph faster than the pitch was delivered, on average, so it’s easy to see that batters really didn’t make hard contact. A lack of extra base power further illustrates this point.

Fulmer didn't allow a single home run or triple on his changeup the entire season and only gave up three doubles. The heat maps below show the frequency of the location in which his changeup crosses the plate in certain count situations.

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In terms of ERA+, Fulmer’s spectacular season was the 25th-best (out of 351) by a rookie pitcher who threw at least 150 innings since the expansion in 1961. Out of those 351 pitchers, the 23-year-old Fulmer was younger than 283 of them. His season was also third-best ERA+ in Tigers rookie history since the expansion.

To say Fulmer had a good season is an understatement. He had an historic season. In fact, Fulmer's year was better in almost every aspect than Justin Verlander’s rookie season, in which he won the 2006 AL Rookie of the Year Award. The only stat categories Verlander edged out Fulmer were in wins and innings pitched. If this is any indication of what we are going to see from Fulmer in the coming years, we are in for a real treat.

Fulmer’s stats with AL & MLB ranks: