I just started a goalie in BAP. It's hard. Making saves isn't too horribly bad (just keep the blue arrow between your goalie's legs and you'll be centered on any shot; easier said than done, that thing's whizzing all over the damn place especially on one-timers), but you're totally at the mercy of your (usually inept) offense as to whether or not you get a win.
Also, unlike regular position BAP, you never go to the bench beyond being pulled because you're down or there's a delayed penalty, so you have to be paying attention like, all the time. I let in a goal because I swatted at a big-ass bug that landed on my leg, for christ's sake, I was furious.