SANTA CLARA -- As it turned out, the 49ers' blowout loss in Seattle was even worse than it looked. Receiver Mario Manningham will miss the rest of the season with an knee injury, according to ESPN.
Reporter Adam Schefter reported via Twitter on Monday night that Manningham sustained a torn ACL and PCL in his left knee during a 42-13 loss to the Seattle Seahawks. Manningham was the team's second-leading receiver, with 42 receptions, and third in receiving yards, with 449.
Manningham came out of the game Sunday after getting tackled by linebacker Leroy Hill in the third quarter. Though the 49ers were mum about Manningham's status earlier Monday afternoon, the receiver was seen making his way into the team's headquarters on crutches.
Losing Manningham, who had already been limited by a shoulder injury, would be another blow for a team with a mounting injury list. All-Pro defensive lineman Justin Smith sat out against Seattle because of an undisclosed elbow injury, and there is no timetable for his return.
Coach Jim Harbaugh said Smith has "an issue that he's working through." Harbaugh added that Smith has not had a procedure to date but, when asked if surgery were a possibility, said: "We'll see."
Tight end Vernon Davis, second on the team in receiving yardage, also was scheduled to be medically evaluated this week. He left the game Sunday with a concussion.
That backdrop might explain Harbaugh's terse news conference
"No explanation, no excuses necessary," Harbaugh said.
The red-hot Seahawks, however, were apparently in a chattier mood. Two Seattle defensive backs, Richard Sherman and Earl Thomas, told Yahoo Sports after the game that the victory felt like payback after Harbaugh taunted them at Candlestick Park on Oct. 18.
Sherman said Harbaugh celebrated the 49ers' 13-6 win that night by driving by the team bus in the parking lot.
"He honked his horn at the bus and waved," Sherman said. He was not present for the incident but said: "That happened -- a bunch of the guys told me. Yeah, he was honking."
Thomas, noting that Harbaugh turned 49 on Sunday, told Yahoo: "Happy birthday -- that's what you get. Yeah, he (honked at us). It seems like he tries to be a professional in front of the camera, but he does his antics, like that, when the cameras aren't around."
Hearing that report described to him Monday did nothing to perk up Harbaugh's mood.
"No, that did not occur,'' he said. "That's a fabrication."
Harbaugh took it a step further by saying he couldn't remember "a time when I've left the game and the other team's still been there this entire season."
The 49ers coach has more important things to worry about in the wake of the worst loss of his San Francisco tenure. He even seemed to agree with another critique from the Seahawks -- Seattle coach Pete Carroll had noted the 49ers' difficulties in getting a play started in time.
Quarterback Colin Kaepernick burned two timeouts with the play clock ticking down and also was flagged twice for a delay of game. That prompted Carroll to say: "They got some delays tonight for whatever reason. They are very deliberate, one of the slowest teams in terms of that. Tonight, it caught them a couple of times."
Harbaugh agreed. "There were a few instances when we were slow," he said.
How do you correct that?
"Fix it," Harbaugh replied.
The 49ers defense, meanwhile, looked vulnerable without Smith, whose status for the playoffs remains in question. Without his havoc-wreaking presence, the 49ers are having a hard time just getting a stop. Consider that over their past six quarters, the 49ers have allowed 73 points and 753 yards. The Seahawks converted on 11 of 12 third-down plays before a kneel-down in the final seconds, and running back Marshawn Lynch rumbled for 111 yards on 26 carries.
Lynch did much of his damage by running in the direction of Smith's replacement, Ricky Jean Francois.
Asked for his thoughts on how Francois played, Harbaugh said: "Rather than go position by position or focus on a particular phase, I don't think any of us will look back on this and say it was good enough. ... (Seattle) had success in multiple areas."