The only way I see MLB working in Sacramento is if the A's end up moving there.
It's only ~90 miles from Oakland, and the market overlaps with the current A's fanbase in Contra Costa and Solano counties.
The only way MLB comes to Sacramento is if the owners want to foot the bill entirely for a stadium. The city won't spend more on a baseball stadium and Raley Field is not really modifiable. They'd have to blow it up and start over the way it was built.
Its definitely messed up the way the fans have been jerked around over this. Unfortunately the problem for a city the size of Sacramento is that the NBA's business model is built around big markets and superstars - small market, unfashionable franchises seem perpetually destined for irrelevance. The fact that the league are desperate for a presence in Seattle again (seemingly at Sacramento's expense) is proof of this. Thats before we even begin to talk about the officiating in the 2002 Western Conference Finals.................