The Cowboys' Jerry Jones was a leading voice among 17 NFL owners on a conference call Thursday that discussed the possibility of halting commissioner Roger Goodell's pending contract extension, sources involved with the call told ESPN. There is a growing difference of opinion among owners about Goodell's overall performance as commissioner, according to sources. The owners on Thursday's conference call are generally unhappy with Goodell and the NFL's front office for a variety of reasons, including the player protests staged during the national anthem, issues regarding the relocation of teams to Los Angeles and the league's handling of the Ray Rice domestic violence case, according to sources. "You don't get to have this many messes over the years like Roger has had and survive it," one owner said during the call. Despite the unhappiness, this group of owners is skeptical that it will be able to outright fire Goodell, according to sources. The NFL would need 24 owners to approve...