Rather than urging her to be a front-runner (because that's lame), bring her up to speed on key teams and players, and let her form her own opinion. Maybe assist her decision-making by mentioning the insatiable monster that is LeBron's ego, but other than a few well-meaning nudges in the right direction, let her decide who she'll be rooting for. Having arrived at her devotion by her own means, she'll feel like she's a true fan, rather than just regurgitating her boyfriend's opinions.