The? Oakland Raiders?are preparing to pursue ESPN analyst Jon Gruden with an offer so strong it could even include an ownership stake in the teams, according to league sources. Gruden will be tempted to accept it, according to sources, but would prefer not to make any decisions until the regular season finishes Sunday and the Raiders make a final determination on their current head coach, Jack Del Rio, who signed a contract extension last summer. But Oakland long has appealed to Gruden, for a variety of reasons: He would return to an organization he didn't want to leave in 2001; he would inherit a young quarterback in Derek Carr?whom he feels strongly about; and he would get to coach a team that is slated to move in 2020 to Las Vegas, where he would not have to pay state tax, as he does now in Florida, where he currently lives. Gruden's contract even could be backloaded to pay him more in the Nevada years of the deal and lessen his tax burden during the California...