Yeah, that's not a problem.
This year, at least, I think the small roster is down to bad luck. During the summer, Christina Buttenham saw here career end due to concussion problems, Bre Cera transferred, Jinaya Houston got to campus and decided she didn't want to play basketball anymore.
We did just sign 4 recruits for next year, though, and only 2 players are expected to leave. That'll take the roster to 13 next year assuming there are no more additions or players leaving. As for why they don't get to 15, I'm not sure. I will say that I browsed other BIG rosters and only a couple of teams are at 15. Most seem to hover around 13.
Yeah, I've pondered for a bit whether the attrition is problematic (whether it's possibly a sign of something wrong in the program). Ultimately I think it's just bad luck. The rumor with each transfer was that the players were homesick, and that seems to checkout because they all transferred to schools closer to home. You obviously can't do anything about a career ending injury, and I can't remember another example of a scholarship recruit leaving the game entirely before his/her Freshman season.
I'll probably dig more into this when I analyze the schedule, but here's a quick preview: I think the starters can compete with anyone in the BIG, though they'd be underdogs against Ohio State and maybe Maryland and Michigan. My big concern is depth (more on that issue soon). Even with the depth issues, I'd say a Top 5 finish in conference is a realistic goal.