What is average MLB fastball speed?

Answer 1

Impossible to answer with absolute certainty, but if you are strictly talking sidearmers and no submariners, that eliminates all but one.

Only Mets righty Joe Smith throws a true sidearm pitch and he sits 89-92 with his fastball.

If you include the submariners such as Byung Hyun Kim, Minnesota's Pat Neshek among others, the average probably drops a bit. Submarine pitchers tend to rely more on deception than velocity and often rush it up to the plate in the 85-88 mph range.

Answer 2

89

Answer 3

88