SANTA CLARA -- Covering tight ends is one of the few flaws in the 49ers defense, and it's been exposed all season.
Of 19 receiving touchdowns allowed, eight have come by tight ends, including one in each of the past four games.
Why are the 49ers struggling against tight ends?
"I'm not sure. I can't say it's been actually that horrific," linebacker Patrick Willis responded. "But it is what it is."
Willis often is most responsible for covering tight ends, and his next matchup will be against the Green Bay Packers' Andrew Quarless in Sunday's wild-card playoff game at Lambeau Field. NaVorro Bowman also could find himself matched up against Quarless, a former Penn State teammate.
"They use the tight end in their offense a lot. It's an important position," 49ers defensive coordinator Vic Fangio said.
Now that the Packers (8-7-1) have a stronger running game with Eddie Lacy, that could make life tougher for the 49ers (12-4) when it comes to defending play-action passes to Quarless.
"Sometimes, as a linebacker, you have to play run and pass, and sometimes a good play-action can get you off a little bit," Willis said.
That's just one aspect of the 49ers pass defense that will be tested against Packer quarterback Aaron Rodgers, who returned from a broken collarbone to defeat the Chicago Bears on Sunday and clinch the NFC North title.
The 49ers have allowed two touchdown passes in each of their past three games. The only quarterback to throw for three touchdowns against them this season: Rodgers, in the 49ers' 34-28, Week 1 win.
One of Rodgers' touchdown passes that game went to Jermichael Finley, who sustained a season-ending neck injury Oct. 20. Finley's replacement has been Quarless, a third-year player who has become a popular target in recent weeks.
"Jermichael went down, and we had a few weeks we didn't get a lot of production out of tight ends," Rodgers said. "Then something obviously clicked in for Andrew, and he's been playing really well the last four or five weeks."
Quarless had back-to-back games of six catches for 66 yards and a touchdown in wins last month over the Falcons and Cowboys. He caught only 3 of 10 passes that came his way in the last two games, for 50 yards.
"He's not as shifty as Jermichael Finley, but he's still a tight end you have to defend," Willis said.
Rodgers has ample targets, elsewhere. Jordy Nelson and Randall Cobb each had touchdown catches in the season opener at Candlestick. Nelson led the Packers with 85 receptions and eight touchdown catches in the regular season, capped by a 10-reception, 161-yard effort Sunday despite being ill. Cobb made Sunday's game-winning catch. San Jose native James Jones and Jarrett Boykin are other threats, as is Lacy.
The 49ers secondary could be playing without cornerback Carlos Rogers (hamstring) for the first time in three seasons, and the Packers surely will test his replacement, likely a combination of Tarell Brown and Eric Wright.
Last game, the 49ers allowed 407 passing yards to the Arizona Cardinals' Carson Palmer, and although Larry Fitzgerald and Michael Floyd accounted for 204 receiving yards, tight end Rob Housler produced five catches for 78 yards.
"They're going to catch their passes," Willis said of tight ends. "The main thing is just not to have any big plays or touchdowns off of it."
Tell that to Luke Willson (Seahawks), Tim Wright (Buccaneers), Tony Gonzalez (Falcons) and Jake Ballard (Cardinals). Those are the tight ends who caught touchdown passes each of the past four games against the 49ers.
"Obviously we didn't do well enough in certain instances," Fangio said. "But, I don't see that as a major problem."
49ers (12-4) at Green Bay (8-7-1), 1:40 p.m. FOX
Jonathan Daniel/Getty Images
Tight end Andrew Quarless (81) has come on strong for the Packers after an injury to starter Jermichael Finley.