Bruise

i had a similar situation during one our baseball teams early season practices this year. throwing bp and i caught one back on the upper left arm. only difference was the size of the ball and it was a real sport with a real athlete at the plate. from 45' or so a baseball can get back to you at an amazing rate of speed i tell ya. never hurt too bad but it swole up like a mother and after about day 2 the bruise covered my entire arm from the elbow to the shoulder, even on the inside into the armpit. maybe thats why you're supposed to keep your whole body behind the L screen.

my arm hasn't even fallen off yet tho, and its been a couple months so thats a plus.