San Francisco 49ers quarterback Colin Kaepernick struggled with his performance during his team's loss to the Green Bay Packers on Sunday.

NBC Sports observed that the quarterback's play was not commendable compared to his previous performances versus the Packers.

"Kaepernick struggled all day long as Green Bay won, 17-3. The win improves the Packers' record to 4-0 and drops the 49ers to 1-3," added the same report.

Though, he reportedly made big passes during the eighth possession, this stopped when he was sacked on a fourth down, with him having a total of six sacks for the game.

According to NBC Sports, his sacks has become Kaepernick's growing problem since "he tries too hard to rely on his legs to bail him out when he's under pressure."

American sports columnist Bill Simmons also wondered on his Twitter account what happened to the performance of Kaepernick.

"What happened to Kaepernick? He can't even make simple throws anymore. Guy came within like 5 yards of winning the Super Bowl. Bizarre," Simmons tweeted.

The quarterback also received criticism from Packers linebacker Clay Matthews who shouted at him during the fourth quarter of game saying, "You ain't Russell Wilson, bro."

"Nah, it's not planned. I was going to hit him with the predator, and then I had a light bulb go off in my head. It's just having fun. We're a bunch of kids out there running around and having fun at each other's expense," explained Matthews in an ESPN report.

But the quarterback claimed responsibility for their loss on Sunday assuring their fans that the 49ers will do better in their next games.

"The only way I know how to fix things is to go back to work. We have to find our rhythm," the quarterback was quoted by the New York Times as saying.

Meanwhile, 49ers coach Jim Tomsula admitted that they have to improve a lot in terms of offense, as per Fox Sports.

"The Green Bay Packers played one heck of a football game and we didn't match it in all three phases. We felt like defensively the guys took a step, offensively we've got to get some things ironed out," he added in the same report.

The coach noted that there is also frustration in the team but noted that they are still confident in what Kaepernick can do.

"I don't think he's [Kaepernick] lacking confidence, that's not the way I would term it. But we've got to collectively on offense, we've got to have 11 people all in the same direction at all times. I do feel we're in the right direction. You don't go around these things, you go through them. So lock your jaw and keep going," explained Tomsula.

The 49ers are set to face the New York Giants on Monday at the MetLife Stadium, East Rutherford, New Jersey.