How did Rogers Centre become a pitcher's park?

TORONTO - One mystery in Major League Baseball is how the Rogers Centre became a pitcher-friendly ballpark.

The topic was again a discussion point in the Toronto Blue Jays' clubhouse prior to a game against the Minnesota Twins in early May. The night before, Toronto's Davis Schneider drove a ball to deep center field, the crowd roared, and some rose to their feet, as many thought the ball would disappear beyond the wall.

Instead, the ball came to rest in the glove of Willi Castro, the Twins' center fielder standing on the warning track.

Across the quiet and mostly vacant clubhouse the next afternoon, one reporter lobbed a question across the space to Schneider.

"Did you think it was gone?" the reporter asked.

Schneider shook his head side to side. He explained he hit the ball slightly off the end of his bat.

Of course, Schneider, a second-year player, has never experienced Rogers Centre as a hitter's paradise. These days, the ballpark sure seems to play differently to many who've seen countless games there.

For most of its existence, the Rogers Centre has been known as a hitter's park, and for good reason. From 1998-2022, it ranked as a favorable ballpark for home runs 18 times, according to Baseball Savant's park factors. It also ranked above average in ballpark factors for run-scoring 15 times in that span.

But the last two years - the post-renovation era - has seen Rogers Centre rank below average in both categories.

Last spring, I was among those who anticipated the renovations would make Toronto's home an even more favorable venue for hitters. Why? Quite simply: the Blue Jays moved fences in more than they raised them or pushed them back - at least by our calculations. That ought to mean more home runs and more hits, as baseball physics expert Dr. Alan Nathan explained.

"To a pretty good approximation, the angle at which the (average home run) descends is about 45 degrees, which is a very convenient number because the tangent of 45 degrees is one," Nathan said.

In other words: For every foot a well-struck fly ball advances forward after reaching its peak, it also drops a foot. That means for every foot the fences were brought in, they needed to be raised by a foot to keep the ballpark home run neutral.

While some areas in left- and right-center fields became deeper, the fences in right field were brought in 16 feet but raised only four.

But Rogers Centre didn't become a launching pad. The opposite happened.

It's a mystery. And to date, an unsolved one.

Last season marked the third-fewest homers at the facility in a full season since 2008 (184), down from 204 in 2022. This year's pace is for 165, which would be the second fewest.

What's going on?

One of the latest theories I overheard while visiting Toronto in May was that airflow had somehow changed due to the lower-bowl renovation. With there no longer space - a void - between the outfield wall and the outfield stands, and with the lower-bowl seating changed behind the infield area, could some sort of cross breeze have been lost, and a different airflow created?

What we know: The ball isn't traveling as well at Rogers Centre the last two years compared to the MLB average for fly-ball distance.

Now, the Jays purposefully traded some bat-first players for glove-first ones in recent offseasons, and the club's hitters are averaging just 307 feet in fly-ball distance this year. That number is a Statcast-era low for the club, and down from 311 feet last year.

For comparison, in 2022, the Jays' average fly ball traveled 324 feet.

(On the road this season, Toronto's fly balls are traveling two feet further - 309 feet - on average.)

And it's not just the Blue Jays; their opponents' average fly-ball distance also resides at Statcast-era lows the last two seasons in Toronto.

Without meteorological equipment, and without knowing if a special, dead ball is being used, and without knowing the humidor settings at the ballpark (those settings and their effect remain something of another mystery), it's difficult to know what's going on, if anything.

What we do have is Baseball Savant.

The MLB-affiliated website uses temperature, elevation, roof status (open or closed), and other environmental factors it defines to account for what is described as "variable extra distance" regarding batted-ball flight.

What does variable extra distance tell us about home environments?

The data asserts that last year, the ball didn't travel as well at Rogers Centre relative to its historical average, but this year, the ball is traveling more like it has in the past.

More confusion.

I asked Blue Jays offensive coordinator Don Mattingly how the ballpark was playing. He wasn't buying the idea the renovations are having much impact.

"Being that it's indoors, I don't know how airflow changes because they changed the lower bowl," Mattingly said. "Last year, they brought right-center in - we thought it was going to be a bandbox. It just hasn't been. It's hard for me to say (why)."

Infielder Cavan Biggio called the Rogers Centre home before and after its makeover.

"I don't think it has anything to do with the renovation," Biggio told me. "When the roof is closed, I feel it flies a little bit better. I know left-center plays really deep. But down the lines it plays pretty short."

To Biggio's point: Slugging to center field at Rogers Centre has fallen from .742 (2008-22) to .624 the last two years. Maybe Biggio's onto something.

What if we isolate exclusively for well-struck baseballs?

There were 429 batted balls hit at the Rogers Centre last year with exit velocities greater than 95 mph and launch angles between 20 and 35 degrees - the conditions most likely to produce a home run.

In 2022, there were also 429 such batted balls.

In 2022, 170 of those batted balls became home runs at the Rogers Centre. In 2023, 167 did - very similar totals.

Overall, though, home runs were down by 20. Weaker batted balls weren't going out as often.

This season, the pace is for fewer well-hit balls (358) and fewer home runs (124) within that batted-ball and launch-angle range.

While ballpark effects attempt to adjust for quality of lineups, a large part of how the ballpark's playing is simply tied to the fact Toronto's hitters are a weaker group than in past years. (The club's pitching was also excellent last season.) The Jays are tied with the White Sox for last in the majors in team bat speed.

Moreover, as we studied earlier in May, the Jays aren't hitting balls to where they most often become home runs: a batter's pull side. The club's approach and underlying skills aren't conducive to hitting for much power.

"Definitely the personnel play into what type of team you are," Mattingly said.

Perhaps there's no mystery after all.

Travis Sawchik is theScore's senior baseball writer.