Quite the similar to Cricket which also has variance on the fences. Sometimes it's only 60m and sometimes it can be upto 90m. The pitch is always 22 yards and the inner circle is always at 30 yards. 

Coinsreporter

They are all with same dimensions foul line to foul line but the fences can be within a range in terms of distance and height. Also the amount of foul territory is variable depending on the stadium.

Stacker_Sports

MLB's Best Ballparks Countdown- #28

grayruby

They are all with same dimensions foul line to foul line but the fences can be within a range in terms of distance and height. Also the amount of foul territory is variable depending on the stadium. 