The contract might have language requiring 6 months of payments for early termination, but typically when you get severance like that, you can't work for a competitor. Is it enforceable? Debatable, but I think it was reported that Lowe was getting seven figures at ESPN, so it probably wasn't in his interests to push the matter anyway.
Also, ESPN fired him as the season was starting, which also seems like a stupid time. (i.e. Paying him for most of the basketball offseason vs. breaking down games, which is more of his area.) Most of their budget cuts haven't really implied much of an overall plan beyond "we need to get costs down because we lost more cable carriage fees this quarter."