Michael Fulmer's Streak of Dominance Has Put Him in Elite Company

Michael Fulmer hasn't allowed an earned run in any of his past four starts. What has led to this sudden dominance?

We've all heard variations of the saying, "it's not how you start but how you finish." It's only been nine starts into the Major League career of Detroit Tigers pitcher Michael Fulmer, but his recent play is quickly erasing an ugly start.

Fulmer owns a 2.52 ERA, a 3.85 Expected Fielder-Independent Pitching (xFIP), and a 23.7 strikeout rate (K%) -- the league average is currently 21.1 percent -- in 53 2/3 innings pitched this season. He is starting to show why the New York Mets used a first-round pick on him in 2011, and why the Tigers targeted him as their return for sending slugger Yoenis Cespedes to the Mets last season.

However, through Fulmer's first four starts this season, it looked like the Tigers got the worse end of the deal. Then Fulmer flipped the script over his next five starts. Take a look at the difference.

Span IP K% BB% ERA xFIP LD% Hard% SwStr% FB% SL% CH%
First 4 Starts 19.1 23.7 9.7 6.52 3.58 24.2 38.7 10.3 62.7 31.2 6.1
Next 5 Starts 34.1 23.8 7.9 0.26 3.98 14.3 22.6 11.2 56.7 25.5 17.8

The difference in Fulmer's ERA in his first four starts compared his next five is a whopping 6.26 points. What changed to help lead to such a drastic difference?

His strikeout rate stayed almost exactly the same, so it wasn't due to more punch-outs, or because of more swings and misses, as his swinging-strike rate (SwStr%) increased by less than a point. It could have something to do with his pitch selection, as that's where the most glaring difference rests.

Looking at the last three columns of the chart shows Fulmer's fastball, slider, and changeup percentages. Over his most recent five starts, Fulmer has thrown both his fastball and slider roughly six percent less of the time, with the difference being made up by an almost 12 percent increase in changeup usage.

Perhaps correspondingly, his line-drive percentage and hard-hit percentage have both plummeted, an indication that we should expect fewer hits and, thus, less scoring. This suggests that Fulmer's recent success is due to inducing overall weaker contact.

FanGraphs breaks down Fulmer's changeup more in-depth here, but regardless as to why he's performed better on the mound, he's on an impressive streak -- and not just for a rookie.

Elite Company

On May 21, Fulmer's fifth start of the season, he struck out 11 hitters over seven innings against the Tampa Bay Rays and allowed just one run. Since then, he has yet to allow another run over his next four starts -- including six shutout innings against the New York Yankees on Sunday -- putting him into rare rookie company.

Perhaps even more impressively, Fulmer has also not allowed more than three hits in any of these four starts, putting him in a group with reigning National League Cy Young Award winner Jake Arrieta.

It's been a helluva run for Fulmer, but his xFIP was actually worse in his five most recent starts compared to his first four, and his 3.88 Skill-Interactive ERA (SIERA) is not hugely better than the current league average (4.03), ranking just 48th out of pitchers with at least 50 innings pitched this season.

The competition he has faced as of late has also not been an impressive bunch.

Team wOBA Runs
Athletics .303 (25) 253 (24)
Angels .309 (21) 271 (17)
Blue Jays .320 (13) 285 (13)
Yankees .302 (26) 247 (25)

Minus the Toronto Blue Jays, no team Fulmer has faced during his scoreless streak has been above-average offensively when judging by weighted on-base average (wOBA) or runs scored. Fulmer did what pitchers should do to these types of offenses -- neutralize them -- but his early-season struggles happened to come against teams with good offenses.

The three teams that hit him the hardest were the Baltimore Orioles, Washington Nationals, and Cleveland Indians. They rank 3rd, 10th, and 15th, respectively, in team wOBA and 8th, 9th, and 10th respectively in runs scored.

It might just be a convenient narrative that Fulmer has struggled against good offenses and thrived against poor ones, and based on his pitch selection, he's been a different pitcher since facing stiffer competition. Regardless, it's something to keep an eye on as the season progresses.

Rest-of-Season Projections

Despite showing Arrieta-like dominance as of late, our projections expect Fulmer to pitch more like a rookie than one of baseball's best starters over the remaining course of the season. We forecast a 4.31 ERA, a 17.6 strikeout percentage, and a 9.2 walk percentage -- league-average is currently 8.3 percent -- in roughly 92 innings pitched.

Even if he does regress, Fulmer's current scoreless streak has been an impressive feat for any pitcher. And he's given us entertaining moments like when he struck out four consecutive Baltimore Orioles hitters on May 15th.

This game was part of Fulmer's rough start -- he gave up five runs in just 4 1/3 innings pitched -- but his recent hot streak has given him the best ERA and xFIP of any starter on the Tigers. Our projections don't think it will happen, but a strong finish could prove that his poor start is a thing of the past.