21. Alex Rodriguez vs. Derek Jeter
Jeter was the Yankee’s main man when Rodriguez arrived in 2004. As the latter’s popularity flared, Jeter became increasingly jealous. In fact, Rodriguez even admired and respected ‘The Captain.’ He wanted to be as popular with his new teammates but this resulted in a massive dent in their relationship.

Once good friends, things deteriorated as Jeter’s envy grew. While they never had a major flashpoint like others on this list, it was more of a cold war. They effectively agreed to remain teammates and coexist without any other personal relationship. In sum, they did what they had to do.