GREEN BAY — The blame extended far beyond the one player who has delivered far more wins than losses in his first 110 pro starts, including the postseason with a Super Bowl victory to his credit.

“I don’t think this is all about Aaron’s performance,” Green Bay Packers head coach Mike McCarthy said afterward.

Yet, there was no arguing that, statistically, the worst game of quarterback Aaron Rodgers’ illustrious career to this point may prove to be costly for the Packers.

A 21-13 upset loss at the Buffalo Bills on Sunday ended the Packers’ five-game winning streak and might prevent them from getting the home-field advantage throughout the NFC playoffs that they greatly crave.

“I don’t like the timing of it, don’t get me wrong,” McCarthy said Monday. “It was not a good day for us.”

And, like the postmortem at Ralph Wilson Stadium, where Green Bay is 0-6 against the Bills, McCarthy made sure to spread the culpability to more than Rodgers.

Never mind that Rodgers struggled through a performance unbecoming of a player who had seemingly separated himself from the other contenders for league MVP by throwing for more than 3,600 yards and 35 touchdowns with only three interceptions in the first 13 games.

On Sunday, Rodgers didn’t have a touchdown pass for the first time since he was knocked out with the broken collarbone early in the loss to the Chicago Bears on Nov. 4 last season. He also had two passes picked off, just a small sample of his career-high 25 incompletions in 42 pass attempts against a stout Bills defense.

Rodgers’ efficiency rating of 34.3 also was a personal low as he threw for just 185 yards.

“Obviously, (Sunday) was well short of the mark, definitely (had) some throws that I usually hit that I missed,” Rodgers said. “And, I have to play better for us to win, obviously.”

Rodgers had plenty of company in why the Packers (10-4) are now back into a first-place tie with Detroit in the NFC North, though the Lions are technically ahead because of their Week 3 home win. The rivals’ rematch to end the regular season Dec. 28 will decide the division champion after the Packers try to rebound when it plays at the Tampa Bay Buccaneers on Sunday.

Green Bay made its once-realistic attainment of the No. 1 playoff seed in the competitive NFC appreciably difficult as Rodgers’ receivers dropped seven passes (a season high in the NFL this season), its defense missed a slew of tackles though it didn’t give up a touchdown and its special teams floundered again by having a field goal blocked and allowing a punt-return touchdown.

“As we viewed the tape (Monday), really our whole football team, I think, was pretty consistent all of the way through — we had way too many mental errors,” McCarthy said. “As a team, our mental errors haven’t been this high in, goodness, way back to the first quarter of the season.

“I thought we were poised for a big day, and it didn’t happen,” he added. “It was not our day.”

REPORT CARD VS. BILLS

–PASSING OFFENSE: D-minus — Bar none, the worst performance by NFL MVP favorite Aaron Rodgers contributed significantly to the Packers’ having their season-best winning streak of five games end and suffering an untimely late-season loss that could prove to be the death knell to their high aspirations of securing home-field advantage throughout the NFC playoffs. Rodgers completed only 17 of 42 passes for 185 yards. Factor in him having zero touchdown throws and more than one interception (two) for the just the second time in his career, Rodgers’ passer rating was a horrific 34.3, his lowest in seven seasons as a starter. The 25 incompletions also is a low-water mark for Rodgers. While he was uncharacteristically off target on a number of passes in the face of little pressure by Buffalo’s predominant four-man rush, Rodgers watched seven different pass targets drop the football. None was more egregious than normally sure-handed wideout Jordy Nelson’s having the ball go through his hands in stride and out in front of the Bills’ trailing defensive backs at the Green Bay 34-yard line on what might have been a 94-yard touchdown in the closing seconds of the third quarter with Buffalo ahead 16-10. Bills safety Bacarri Rambo had both picks of Rodgers, who came into play with only three interceptions on the season and none in the preceding five games. The Bills clinched the upset victory when All-Pro defensive end Mario Williams whipped right tackle JC Tretter, who came on in relief of a concussed Bryan Bulaga in the final quarter, and knocked the football out of Rodgers’ right hand. That lone sack of Rodgers resulted in a safety for Buffalo as halfback Eddie Lacy illegally touched the fumbled football in the end zone while trying to advance it out with less than 2 minutes to play. Cobb managed to have a productive game amid the drops-induced malaise coursing through the receiving corps with game highs of seven catches and 96 receiving yards in 13 targets.

–RUSHING OFFENSE: B — Led by Lacy, the Packers rushed for more than 150 yards for the third time in the last four games. An explosive run of 12 yards on the first play of the game foreshadowed another productive outing for Lacy, who shook off a bruised hip that knocked him out of Green Bay’s win over the Atlanta Falcons just six days earlier. In what turned out to be the Packers’ only touchdown drive of the game, Lacy started it with three straight runs of 15, 17 and 22 yards between the tackles and finished it with a one-yard dive across the goal line early in the second quarter. Lacy had 10 carries for 73 yards in the first half, but his touches and output tailed off considerably the last two quarters as he finished with 97 yards in 15 touches. A holding call on left guard Josh Sitton wiped out a 21-yard run by Lacy in the fourth quarter. Rodgers (on a 19-yard scramble), James Starks (12 yards) and even Cobb (12 yards), who lined up some in the backfield in the second half, each had an explosive gain.

–PASS DEFENSE: B-minus — For the most part, Green Bay’s oft-criticized defense had a nice bounce back coming off a horrendous second-half showing in the narrow win over the Falcons. It helped the Packers were facing a mostly pedestrian Buffalo offense helmed by veteran Kyle Orton. Although Orton incredibly improved to 5-0 in home games played against Green Bay, his numbers were as bleak as they have been in prior meetings. Orton threw for only 158 yards and didn’t lead the Bills to end zone once as they settled for four field goals. Plagued by a few drops, Orton also missed some open receivers and underthrew rookie standout Sammy Watkins (one catch for 28 yards in six targets) on a deep ball along the sideline that had cornerback Tramon Williams in position to make a leaping interception in the second quarter. That potentially game-changing takeaway — the only one for Green Bay — with the score tied at 10 went for naught, however, as linebacker Sam Barrington drew a penalty for unnecessary roughness at the end of Williams’ runback that pushed the starting point back inside the Packers’ 20. The defense also had a huge communication breakdown that allowed running back Bryce Brown, who was flanked out to the left, to be uncovered on a third-down corner blitz for an easy 40-yard completion by Orton in a third-quarter possession that led to a field goal for a 16-10 Bills lead. The pass-rushing pressure was adequate on Orton, who was sacked three times, including two by linebacker Clay Matthews.

–RUSH DEFENSE: C — Thanks to a resurgence in the second half aided by a multitude of missed tackles by Green Bay, the Bills almost gained as many yards on the ground as they did through the air. Buffalo had just 34 rushing yards in 11 attempts at halftime. A concerted effort to chew up clock in the second half and nurse the gradually growing lead paid dividends as the Bills finished with 113 yards. Veteran halfback Fred Jackson inflicted the most damage with 71 yards in 20 carries with a long of 13. His two-yard pickup on a second-and-2 run near midfield was bigger than the modest gain because the fresh set of downs for Buffalo forced the Packers to burn the last of their timeouts inside the 3-minute mark. All of that came after Green Bay failed to recover a fumble by back Boobie Dixon in Bills territory with more than three minutes left and then had a neutral-zone penalty on Barrington to set up Jackson’s shorter run for the pivotal first down.

–SPECIAL TEAMS: D-minus — An Achilles’ heel for most of the season, another week of special-teams failures couldn’t be masked in this one. Poor downfield coverage gave Marcus Thigpen the crease to break away for a 75-yard touchdown return on a punt by Tim Masthay late in the first quarter. Then, in the second quarter, defensive star Mario Williams busted through the middle of Green Bay’s line to swat away a low-trajectory 53-yard field goal from Mason Crosby. That’s the sixth block of a Packers kick this season. Crosby connected on his two other field goals, from 45 and 34 yards. A season-high-tying six punts for Masthay left him with subpar averages of 42.8 gross yards and 30.3 net yards despite a season-long boot of 63 yards that was downed at the Buffalo 2 late in the first half. Masthay had to re-kick twice earlier in the second quarter because of successive penalties on the Packers. Green Bay had next to nothing on returns — Cobb and Micah Hyde combined for five yards in two punt runbacks, and DuJuan Harris was taken down after only eight yards inside the Green Bay 20 on his lone kickoff return.

–COACHING: D — A season-low 253 yards allowed by the Green Bay defense didn’t matter because its previously high-scoring offense was putrid, mustering all of 333 yards. As much as procuring a fourth straight NFC North title will be theirs for the taking when they host the Detroit Lions in the Dec. 28 regular-season finale, Sunday’s flop outside Buffalo could be costly for the Packers’ postseason fortunes. It’s a game they needed to win to stay on the inside track for home-field advantage. Mike McCarthy made some perplexing decisions that contributed to the downfall. He went away from liberally running the football with Lacy after his big first half, instead positioning Cobb in the role of running back on a number of plays. McCarthy also admittedly cost Rodgers and the offense from possibly saving face and pulling off a last-second comeback win by leaving the untested Tretter on an island against the speedy Williams on the decisive strip-sack for a safety near the end of the game. Meanwhile, the ugly evidence continues to mount against longtime special teams coordinator Shawn Slocum for a seemingly weekly occurrence of blunders by his units.