What's with the sudden spike in home runs? And will lengthy IL stints ruin these pitchers' seasons?

Despite MLB’s public pronouncements that the baseballs will be more uniform this season because all 30 parks are using humidors for storage, the results on the field seem to tell a different story.

For the first month or so of the 2022 regular season, balls weren’t flying as far as they did a year ago. That was in line with MLB’s plan to encourage hitters to put more balls in play and not just swing for the fences. The numbers fell in line, with home runs hit at roughly 35% below their expected rate, according to the research site BallparkPal.com.

Then something seemed to change – almost overnight.

Around May 14, home run rates jumped roughly 10 to 15 percentage points over what batted ball data would have projected. They’ve maintained that level over the course of the last month of games. And it’s not because of warmer weather; that’s already factored in.

Could a difference in the properties of the baseball be the culprit? MLB has a history of changing the ball in the middle of the season without telling anyone. Thanks to the work of researchers Dr. Alan Nathan, Dr. Meredith Wills and others, we now know a lot more about the impact even the slightest changes can have on how the ball flies.

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League-wide slugging before May 14 was a paltry .375, but in games since then (through June 12) it jumped to .410. However, the expected league-wide slugging percentage was exactly same (.438) both before and after.

Also, when batters hit fly balls in the early part of the season, they ended up as home runs 10.3% of the time. Since May 14, they’ve left the yard at a 12.2% clip. (Over those same dates in 2021, the gap was much smaller – 13.1% vs. 13.9%.)

But all fly balls aren’t the same. Let's look at balls hit at the optimal angle and exit velocity to produce home runs, which Statcast classifies as “barrels.” Jon Anderson of Rotoballer recently broke down how often those barreled balls have gone for homers this season – with the numbers staying even in April, increasing slightly in early May and jumping significantly right around that May 14-15 weekend.

Taking his idea a step further, I looked at the HR/barrel rate from the April 7 start of the season through May 13. It was 47.2%. From May 14 through Sunday’s games, it rose to 59.0%. 

(Last year, using the same dates, the difference was much smaller: 56.1% vs. 59.8%. And just for fun, during 2019's home run explosion, the rates were 71.1% and 76.9%!)

The obvious question now is … where do we go from here? Will the fly-ball hitters who struggled earlier in the year begin to thrive again? Will we see an even livelier ball in over the summer? Or will the humidors have the opposite effect in the hottest and stickiest months by taking moisture out of the baseball?

Unfortunately, this kind of analysis usually leads to more questions than answers. For now, just being aware of the prevailing batted-ball trends may be the best we can do.

Pitchers finally getting healthy

In-season injuries can be devastating to MLB and fantasy teams alike. However, there’s also a sense of excitement when those injured players return to the active ranks.

Right now, several high-level starting pitchers have just come off the injured list or are almost ready to be activated after extended absences.

-- Shane Baz, Tampa Bay Rays. Following arthroscopic elbow surgery in March, Baz looked dominant in four minor league rehab starts. However, the Twins roughed him up for five runs over 2 1/3 frames in his June 11 return. Consider that just a blip on the radar.

The Rays have been very careful with Baz, and the innings limit they might have put on the 22-year-old right-hander shouldn’t be a factor now that he's already missed two months.

-- Clayton Kershaw, Los Angeles Dodgers. The three-time Cy Young winner was off to a fabulous start (4-0, 1.80 ERA) until a pelvic injury sidelined him for a little more than a month. Returning to the mound Saturday in San Francisco, he lasted only four innings and took the loss. But as with Baz, the first start back has a tendency to be the roughest.

-- Lance Lynn, Chicago White Sox. The veteran righty was coming off arguably the best season of his career (2.69 ERA, 1.07 WHIP over 28 starts) when he suffered a slightly torn knee tendon in April. After a lengthy recovery period and three shaky rehab starts, he allowed three runs and 10 hits in 4 1/3 innings vs. the Tigers.

At 35, it may be a stretch for Lynn to stay healthy the rest of the way, but he should provide solid stats whenever he takes the mound.

-- Chris Sale, Boston Red Sox. The left-hander reportedly hit 96 mph on the radar gun this week at the Red Sox’s spring training facility. That’s a great sign as he works his way back from the stress fracture in his ribcage he sustained pitching to college hitters during the lockout.

After tossing just 42 2/3 innings last season in his return from elbow surgery, Sale could come back as a reliever later this month as a way to build up his arm strength.  

-- Lance McCullers, Houston Astros. McCullers, 28, posted an excellent 3.16 ERA last season but couldn’t pitch in the ALCS or the World Series due to nagging pain in his forearm. He’s just now throwing curveballs again, which means he’ll likely remain out until the All-Star break. But there’s a spot waiting in the Astros rotation once he’s ready.

-- Jacob deGrom, New York Mets. The wildest of this season’s injury wild cards, deGrom has progressed to throwing bullpen sessions as he works his way back from a shoulder injury. The Mets have been targeting a return around the All-Star break for their ace, who hasn’t pitched since last July 7. That would still leave close to half a season – with his 1.08 ERA and 146 strikeouts in 92 innings from a year ago a reminder of what deGrom could still accomplish if healthy.

Follow Gardner on Twitter @SteveAGardner