Washington Redskins coach Mike Shanahan’s short leash is about to become a choke collar. Only one Redskins coach ever — Bill McPeak — has reached a fifth season with as sorry a winning percentage as Shanahan’s .421. Norv Turner was .454 at 49-59-1 from 1994 to 2000 and was considered a big disappointment. Like Shanahan, Turner inherited an aging team with little remaining talent and a young quarterback, but at least the former Cowboys offensive coordinator reached sustained mediocrity after two seasons. Shanahan supporters, if there are any left after the Redskins’ loss to Minnesota (2-7), can claim the coach faced a salary cap sanction, but that pales in comparison to what Turner dealt with: an owner’s death and a team being run by an estate trust board that wouldn’t let Turner keep his free agent quarterback. The Redskins look headed for their third 10-loss season in four years under Shanahan. Only McPeak managed worse numbers at 21-46-3 for .313 over 1961-65 and still saw the fifth year. Sure, Shanahan did a fine job last season to win seven straight games and an NFC East title. But then he completely blew the playoffs and maybe this season by letting quarterback Robert Griffin III remain in the Seattle game to get hurt. Owner Dan Snyder could have terminated Shanahan then without remorse. This was supposed to be the season the Redskins made the jump to Super Bowl contender. Instead, special teams are just trash. The defense has been largely horrible and surrendered two big late leads in three games. Minnesota changed quarterbacks and still blew by Washington. The offense, as expected with Griffin’s injury, started slowly. The quarterback needed a month to get his legs back and another month to regain his mental edge. But offensive coordinator Kyle Shanahan didn’t help with poor play-calling and an obvious problem meshing with Griffin’s limited capabilities while he was recovering.