Which MLB ballparks could use a change in dimensions?

The Kansas City Royals announced that they would be altering the dimensions of their home ballpark, Kauffman Stadium, for the 2026 season. 

Across the outfield, the fence will reportedly be brought in by 10 feet. Additionally, the height of the walls will be shrunk by a foot-and-a-half down to 8 ½ feet.

For years, Kauffman Stadium has been one of the most difficult stadiums to hit a home run in. It saw only 151 home runs hit, the fifth lowest, in 2025. Despite this, Kauffman Stadium still ranked as the sixth friendliest offensive stadium, according to Baseball Savant. That ranking takes into consideration that the ballpark allowed the eighth-most doubles (272) and third-most triples (35) last season. 

The team reasoned that it didn’t want to see its players having to change their swing in an attempt to hit the ball harder just to hit a home run. Royals general manager J.J. Picollo said, “We want a neutral ballpark where if you hit a ball well, it should be a home run.”

Unlike other sports with regulation-sized fields, baseball allows for some personality and quirks as long as the bases are 90 feet apart and the pitcher's mound is 60 feet and six inches away from home plate.

Each team's park should be different from one another while simultaneously aiming to keep a neutral playing ground.  

Which ballparks could use a change in dimensions? 

What is Park Factor?

First, what is Park Factor? Park Factor will be brought up many times, and to put it simply, it is how the field of each stadium affects the game. 

Park Factor takes into consideration elevation, distance and height of the walls, average wind and weather. 100 is an average score; anything lower is pitcher-friendly, and anything higher is batter-friendly. 

Offensive composition

The bottom-ranked teams for Park Factor include the San Diego Padres, Milwaukee Brewers and Cleveland Guardians, all ranked at 97, and Seattle Mariners with 91. 

Before the changes, Kauffman Stadium had a good balance in production: a low amount of home runs but a good contrast of doubles and triples. The four named teams buck that trend. 

All of the stadiums of the four named teams rank in the bottom six in slugging percentage, all but Seattle rank in the bottom 10 in home runs and all rank in the bottom 12 in doubles. 

Across the board, offensive production is down, barring the occasional superstar like Seattle's Cal Raleigh, Cleveland's Jose Ramirez or San Diego's Fernando Tatis Jr.

Each field has a flaw. For Cleveland, it's the 19-foot wall in left field. For San Diego, it's the deep walls in the left and right field gaps. For Seattle, it's an uncomfortable batter's eye, and for Milwaukee, it's a combination of the batter's eye and the wind when the dome is open.

These things may seem small, but something as simple as the stadium setup causes batters to have a slightly harder time seeing the ball, which can make a huge difference. 

For teams like San Diego, Cleveland and Milwaukee, rather than composing rosters built to hit it over the gaps or over the tall wall, rosters are comprised of guys who hit for average and play good defense to complement the pitchers. 

When visiting teams come to play, it feels less neutral. The visitors aren't used to the ballpark that the home roster was created around, giving a major homefield advantage.

Final verdict

The average MLB stadium is 331 feet to left, 405 to center and 326 to right. None of these four stadiums is that far off from those marks. 

Back to the comments of the Royals GM. The changes are to ensure a neutral ballpark. 

Baseball is quirky, stadiums are different, but each stadium should have equal playing ground. Each stadium mentioned here doesn't have a difficult fix. 

Seattle may be costly with a new, more hitter-friendly batting eye. Same for Milwaukee, but consider keeping the window closed more for the wind.

San Diego could go in either direction: Move the walls in at the gaps to make it a more well-rounded ballpark with more home runs, or push the fences back by the foul poles to make more doubles and triples. 

For Cleveland, the big wall in left field doesn't necessarily need to go. If they want to keep the height, then maybe bring the wall in. If not, push it out and lower the height. 

These changes would ensure more parity in terms of an even playing ground for the home team and all visitors.