Why are pitchers getting hurt more often?

Justin Verlander has yet to make a start this season due to an arm injury.

Justin Verlander was scheduled to make his first start of the season on Tuesday against the New York Yankees, but that plan was scrubbed when his arm didn’t respond well after a simulated game last Wednesday. It’s unclear when Verlander will take the mound for the Detroit Tigers in 2015.

Now 32 years old, Verlander is coming off his worst season which came on the heels of core muscle surgery last January. He admitted that he probably rushed his return and was never 100% in 2014 though he still made 32 starts and logged more than 200 innings for an eighth straight season. Now his arm is sore which puts JV in a category with a lot of company: injured pitchers.

Arm injuries are at an all-time high 

According to one study, arm injuries to pitchers that require surgery are up an alarming 70% in the last two years. Since the end of the 2013 season, more than 60 major league pitchers have undergone Tommy John surgery, which is as many as in 2011-13 combined. On the current Detroit 40-man roster, four pitchers have had the surgery during their career: Joba Chamberlain, Joe Nathan, Bruce Rondon, and Joakim Soria.

Why are so many pitchers suffering serious arm injuries in modern baseball? Starting pitchers are pitching fewer innings, often going just 5-6 innings per start. They’re getting fewer decisions and the complete game is exceedingly rare — last season the A’s and Astros led the AL with seven, while as recent as 1990 Jack Morris had 11 all by himself. So what gives?

The answer is not in the innings, it’s in the way pitchers are throwing.

Fewer batters faced, but more pitches

Let’s take Verlander for example: he had his first full season in 2006 when he won the Rookie of the Year Award. The righthander logged 186 innings and faced 776 batters, not a daunting load for a starter. Contrast that with Morris who in his first full season (1979) pitched 197 2/3 innings, completing nine of his starts. That season, Morris faced thirty more batters than JV did in his rookie year — 806. Morris was 24 years old, Verlander was 23. But Verlander actually threw more pitches than Morris did — 2,968 to 2,740. That trend is one of the two big reasons that starting pitchers today endure more stress to their arms. Throughout Verlander’s career he’s averaged almost four pitches per batter faced (3.94 to be exact), while Morris, the workhorse of his generation, averaged 3.4 per batter faced. That may not seem like a big difference, but over the course of a full season that results in 500 more pitches. Even when you factor that today’s starters face about 125-150 fewer batters per season than Morris and his brethren did, the workload (judged by pitches thrown) is heavier for the current pitcher.

Modern pitchers like Verlander are throwing more pitches because they are throwing more strikeouts and the strike zone is smaller than it used to be, therefore more 3 ball counts are happening.

Throwing harder more often

The second reason modern pitchers are getting hurt more often is velocity. Back in the 1980s the average fastball in the big leagues was somewhere between 84 and 87 miles per hour (figures vary depending on the source). In 1995 the MLB average hit 88 miles per hour for the first time, and in 2002 it was 89.9 MPH. By 2014 the speed of the average major league fastball soared past 92 MPH and that figure will surely rise a bit in 2015.

Big league pitchers are throwing harder than ever before and they are exerting more effort than ever. There was a time when starting pitchers learned to “pick their spots” (what Hall of Famer Christy Mathewson called “pitching in the pinch”), selecting a few times per game to “dial up” their fastball when needed. A starter often “pitched to contact.” Mickey Lolich once said that he liked to “let the batter get themselves out.” But today, many starting pitchers are throwing near maximum velocity from the first inning on. Even if they do pick their spots, they are throwing harder and with more torque on their arms than pitchers ever have.

Between 2006 and 2013, Verlander threw nearly 29,000 pitches, a total that was more than 1,200 more than any other pitcher in the game. He faced 7,302 batters during that stretch, while no other pitcher reached 6,900. Verlander was a workhorse but he also threw hard…real hard. In his three best seasons (2010-12), Verlander’s fastball averaged 94.8 and he frequently reached the 99-101 MPH mark. But that workload and velocity has had its toll, and now the former MVP is feeling it in his right arm.

Verlander will need to reinvent himself

We don’t know if Verlander will need Tommy John surgery (the symptoms he’s reporting thus far don’t match that type of injury), but we have seen that since his 30th birthday his body has started to squawk and his effectiveness has waned. In the last two seasons his K rate (strikeouts per nine innings) fell from 8.9 in ’13 to 6.9 in ’14. That’s usually an indication that a power pitcher has started to enter a decline phase.

If they can stay healthy, many power pitchers can make adjustments and pitch well into their 30s. That’s what Verlander will need to do once he gets back in the rotation. He will never be the pitcher he was when he was toying with no-hitters in his prime, but JV can be a very good pitcher if he overcomes this injury and learns to pitch more efficiently and without the velocity he once had.