Re: USMMA.
I know well two baseball players. Sea Year did not interfere with baseball. Served after baseball season and returned in late fall.
A graduate has a six (?) year stint in the Reserves as an officer. Two weeks a year are given to USN - however, if a graduate desires, he can go into active service with a wide array of choices, including combat arms as well as ships.
Graduates are not limited to sea duty; I know grads who work in ports (a 9 - 5 job); I know grads who ship out for six months at a time and are off (but still collecting vacation pay) for much of the rest of the year (and earn six figures).
Not a college for everyone, but the grads can work wherever and whenever each wants. (Basically show up at the union hall and head out to sea, or take "day" jobs at the port. One grad I know times his voyages to baseball season - he coaches HS baseball.) Promotions (from third, to second, etc.) are based upon hours worked, so a grad constantly at sea rises quickly.