If you go to the lineup screen for a future game, you can select the lineup for the 5 most recently played games to determine the depth chart. If you then go to the box score for the game in question, you can see the minutes played for each player. As long as a player didn't play two positions, you can just find the 2 or 3 players whose minutes at each position add up to 48. And even if one player split time, you can probably figure out the split.
Or you could watch the match replay.
In basketball, positions are numbered, a point guard is "a 1", shooting guard "a 2", small forward "a 3", power forward "a 4", center "a 5".
(http://en.wikipedia.org/wiki/Forward_(basketball)#Front_c...)In a discussion, a player who is a guard might be described as "he's really more of a 3 than a 2", which probably means he is somewhat taller and can play inside a little more than a pure shooting guard.
The BB scoreboard and lineup screens order the positions in the same order.
In reality, a player can't really be said to play a particular position. With a small court and only 5 players, players do take different roles from play to plat, so you probably wouldn't see position reported in a box score, like you would in a baseball box score. But it would be handy for BB to show it anyway because of its importance to the game engine.