There are 3 different cases for the starting lineup.
Case 1: Bob starts (and Yogi doesn't). In this case, the coach must choose 4 more players from the 10 remaining players (remember that Yogi won't play, so there are only 10 players left to select from). Thus there are 10C2 lineups that the coach can choose.
Case 2: Yogi starts (and Bob doesn't). As in Case 1, the coach must choose 4 more players from the 10 remaining players. So there are 10C4 lineups in this case.
Case 3: Neither Bob nor Yogi starts. In this case, the coach must choose all 5 players in the lineup from the 10 remaining players. Hence there are 10C4 lineups in this case. To get the total number of starting lineups, we add the number of lineups in each of the cases:
Case 1 + Case 2 + Case 3 = 210 + 210 + 252 = 672
Bogus Solution:(This is what I did the first time
)
Case 1(and 2): Bob is in the team but Yogi isn't. There are 11 people that can be on the team. 11 * 10 * 9 * 8 * 7 * 2(for Yogi's case). That is 110880.
Case 3: neither are on the team. 10 * 9 * 8 * 7 * 6 = 30240
Sum is 141120
Way off
+355 
