Most professional athletes are extremely competitive by nature. If they weren't, they probably wouldn't be professional athletes.
These guys are constantly jockeying for position in their respective game. Not only are they dealing with challenges from the opposition, there are additional internal factors at play as well.
Oftentimes the fiercest feuds are between guys sharing the same locker room. Wearing the same jersey brings them together as a team, but it should never be mistaken for a blanket pledge of loyalty.
The minute someone gets complacent in their position is the minute some backstabbing jerk face is going to come in and steal his girl. Or at least try to steal his girl. Or maybe just try to get her in bed.
Whatever though. All I'm saying to the fellas is to look alert and keep an ear to the ground, because you never know when someone you trusted—maybe even your best bro—is going to swoop in and do you dirty.
If it happened to these guys, it can happen to anyone.