Coach Jay Gruden was mystified after Monday’s 28-13 loss to the Philadelphia Eagles, saying the team’s defense has too much talent to be playing poorly. And they are playing poorly. Over the last five games, the Redskins have given up an average of 430.4 yards per game — trailing only the Cincinnati Bengals in that span. They’ve also allowed opponents to complete a staggering, league-high 54.1 percent of their third downs in the last five games. That’s a dramatic falloff from earlier in the season. “We have to do everything better on defense — we have to step up our game to heights that we never have before and it just has to be done in order for us to get where we want to get,” Gruden said.