OAKLAND -- Raiders offensive coordinator Greg Knapp is too busy trying to score touchdowns to listen to critics.
"I've been in this business long enough to know if you're not winning, or if you're not moving the ball or scoring points, you're going to get criticized," Knapp said. "I was in San Francisco for nine years when they were finishing up the run of five Super Bowls.
"Even then, when they were winning, you couldn't win well enough. There's always going to be criticism. That's part of the job."
By any statistical measure, the Raiders (3-10) have regressed on offense in 2012.
Going into their game against the Kansas City Chiefs (2-11) at O.co Coliseum on Sunday, scoring is down to 19.1 points per game after averaging 22.4 in 2011 and 25.6 in 2010 with Hue Jackson running the offense.
After scoring 37 offensive touchdowns in 2010 and 36 in 2011, the Raiders have 25 touchdowns in 13 games this season. With three rushing touchdowns, the Raiders are ranked last in the NFL. In 2010 and 2011, the Raiders had 35 rushing touchdowns in 32 games.
Coach Dennis Allen, who hired Knapp to overhaul the offense from one with a power-based running game with drop-back passing to a West Coast scheme with a moving pocket and zone blocking, said he has no regrets.
"There's been a lot of change, and when there is a lot of change, sometimes you don't get the results you're looking for right away," Allen said.
Allen would get an argument from the fan base on social media, with Knapp rating as public enemy No. 1 on Facebook and Twitter.
The prevailing opinion among the fan base is that the Raiders switched from an offensive system that worked reasonably well to one that doesn't necessarily suit the talent on the roster.
"I'm a firm believer in the scheme," Knapp said. "I've been to too many places and had too much experience to (not) know it's a productive scheme ... you'd much rather have a coach come in and teach what he knows best than have someone try and teach a system that he doesn't know at all."
Knapp said position changes and injuries have played a role in the offensive difficulties. Stefen Wisniewski missed much of training camp with a calf injury and moved from left guard to center. Right guard Cooper Carlisle moved to left guard to make way for free agent Mike Briesel, and Khalif Barnes was replaced by Willie Smith for seven games because of a groin injury.
Running back Darren McFadden and backup Mike Goodson each missed four games with high ankle sprains. Returning wide receivers had to learn a new system and were joined by rookies Juron Criner and Rod Streater.
"If you take a business structure and you make those changes, it's going to take a year's time to process everything and learn it," Knapp said. "Once they master it, you can add to it. Right now, it's taking some time."
The Raiders are ranked 30th in rushing at 81.2 yards per game, but their run blocking has improved, with backs averaging 4.5 yards per carry in the past four games.
"I'm very pleased with the fact that we're the top 10 in passing and we've improved in the running game the last six weeks," Knapp said. "We're not where we need to be in scoring points. That's what I'd like to get better at, finishing drives and getting more big plays for touchdowns."