My son has done this a few times. He always carries on his gloves, catcher's gear, and uniform jersey (i.e. the things he can't borrow from teammates). The first two times, he packed his bats in his catcher's bag, surrounded by clothes and checked the whole thing. The most recent time he packed his bats in a marucci bat quiver (fits three bats) and checked that separately from this gear bag (still filled with clothes). Although bats are expensive, they are the easiest thing to borrow or replace on short notice.