"I see two potential buyers.
1. FOX - (Since it is the largest market without an O&O).
2. Tribune - Same thing as #1, even Tribune is no longer selling out their property after Sam Zell brought the remainder of the company."
The possibility of Fox buying KRON has been discussed before. While "Fox 4" does have a nice ring to it, I don't think so. From what I understand, News Corp has been selling stations lately, I don't think they're interested in acquiring any new ones. As an outsider, I've noticed that all the media corporations now seem perfectly comfortable sharing content with direct competitors. Some examples - CBS producing sitcoms that run in NBC primetime. 20th Century Fox producing primetime shows for all of the networks. In LA, CBS bought KCAL 9, and there was all sorts of speculation that when the WB and UPN combined to make the CW, it would be aired on KCAL. That's what happened in SF, when KBWB lost out, and the CW went to CBS owned KBHK/44. Not so in LA - the former WB affiliate - Tribune owned KTLA 5 got the CW, and KCAL remained independent.
Final example - I took my kid to Universal Studios in LA last week - there are Nickolodeon tie-ins and attractions all over Universal. But NBC owns Universal, and CBS owns Nick. Obviously, the media giants do all of this because "synergy" is just good business. Fox doesn't need to spend a lot of money to buy KRON - they've done just fine with KTVU for years now.