There is no definitive answer to this question as it can vary depending on the dimensions of each individual ballpark. However, based on research and various opinions from experts in the field, it is generally agreed that the team with the deepest outfield in MLB is the Boston Red Sox. The Fenway Park outfield has a depth of 420 feet from home plate to center field, and 380 feet from home plate to both left and right field. This gives the Red Sox a significant advantage over other teams when it comes to playing deep fly balls.
