The Denver Broncos have a good defense.

According to Pro Football Reference, the Broncos entered their Week 9 matchup with the Philadelphia Eagles ranked ninth in points allowed, third in pass defense and first in run defense.

For the last two-and-a-half seasons, dating back to the 2015 Super Bowl season, the Broncos’ defense has been so good it has masked how poor the offense has played at times. The Broncos offense couldn’t hide behind the defense during Sunday’s 51-23 loss to the Philadelphia Eagles.

Just as the defense has bailed out the offense when they have a bad day, the defense needed some help keeping up with Philadelphia’s high-flying offense on Sunday, and that help never came. The last time the Broncos gave up 50-plus points was Week 7 of the 2010 season in a 59-14 loss to the Oakland Raiders.

Before Sunday, the Broncos hadn’t allowed 30 points in a game this season. They allowed 31 in the first half alone in Philadelphia.

Before Sunday, the Broncos hadn’t allowed a rushing touchdown on the season. Three of the Eagles’ seven total touchdowns came on the ground. Excluding touchdowns scored on interception returns, fumble returns and punt returns, the Broncos defense had allowed seven touchdowns combined in their last five games.

Before Sunday, the defense had played well enough to win all four of the games the Broncos have lost. Sunday might have been the straw that broke the camel’s back.

Opposing teams facing the Broncos defense averaged 188.1 yards per game through the air and 72.9 yards per game on the ground. The combination of Carson Wentz and Nick Foles threw for 234 yards (222 NET after sacks) while the Eagles’ running game accounted for 197 on the ground.

While the defense has done a good job of keeping opposing teams out of the end zone and off the scoreboard, the one knock they have received this season has been the lack of turnovers they have forced. While the turnovers are starting to come (they have three in the past two games), they aren’t getting any help from their offense in that department. Brandon Marshall scooped up a Nick Foles fumble and returned it for a touchdown in the fourth quarter of Sunday’s loss, but two Brock Osweiler interceptions brought the Broncos’ turnover differential to a minus-12 on the season. The Broncos are now tied with the Cleveland Browns for the worst turnover differential in the NFL. (Cleveland had a bye this week.)

The defense has carried more than their fair share of the load for some time now, but the levee was bound to break eventually. The Broncos could very well get back to playing solid defense as the season progresses, but, like Sunday, they are going to need some help from the offense moving forward.

With the turnover differential no longer in their favor, the offense can’t hide behind the defense any longer.