Brock Purdy isn't the only problem for the 49ers

In Week 8's 31-17 loss, Cincinnati Bengals quarterback Joe Burrow diced the 49ers defense for 283 yards and three touchdowns while completing a career-high 87.5 percent of his attempts. The previous week against the Minnesota Vikings, quarterback Kirk Cousins posted a season-high 77.8 completion percentage and 378 passing yards.

Dating back to its Week 6 loss to the Cleveland Browns, San Francisco has allowed 24 points per game compared to 13.6 points during its 5-0 start. The defense has given up 395.3 yards per game during the three-game losing streak, including 272.7 passing yards and 122.7 rushing yards (at an average of 4.5 yards per rush attempt).

In the team's 5-0 start, the defense allowed 266.8 yards per game, including 202.6 passing yards and 64.2 rushing yards (at an average of 3.7 yards per carry).

San Francisco's inability to get sacks has been an issue all season and the pass rush did a poor job of impacting Burrow on Sunday a week after the 49ers failed to record a sack on Cousins. The defense is 18th in the league in sacks with 18 after Sunday's afternoon games, far too low for a team with talent along the line including Nick Bosa, Javon Hargrave, Javon Kinlaw, Arik Armstead and Randy Gregory.  

The 49ers get their bye week at the perfect time in Week 9, giving them time to reset and get ready for the stretch run. They will need to figure things out in a hurry because the schedule does them no favors.

Three of San Francisco's four games immediately following its bye are on the road against the Jaguars (6-2), Seahawks (5-2) and Eagles (7-1). All three have offenses capable of exploiting San Francisco's suddenly vulnerable defense.

Purdy can help the unit by not putting them in bad situations with turnovers, something that has become a problem for the second-year quarterback. He's thrown five interceptions during the last three games after throwing none the first five weeks.

He isn't making the defense's job easier and the same can be said about how the defense has impacted Purdy. Both need to be better for the 49ers to get out of their funk.