The former series champion was in 12th place in the standings heading into the final race before the play-off but his Richmond weekend did not get off to a good start after he qualified only 28th, the worst among those fighting for a place in the Chase.
During the race Kenseth struggled to find the speed to move to the front and had problems in the pits as well, even missing his box once. He eventually dropped a lap down to the leader and although he was able to get it back during the final caution, his 25th place finish was not enough for him to stay inside the top 12.
"This is about how we ran the last four Richmond races," said Kenseth. "We just haven't been competitive, so, really since California it's been a downhill slide for us.
"We slowly fell back in the points every week, so I can't say I'm very surprised we didn't make [the Chase], but we've been working on it hard, we're just weak in a few areas. We need to figure out why because none of our cars really run the way they should.
"I wish we weren't in this spot, but we did the best we could and we'll try again next week."
Kenseth still seems puzzled by Roush Fenway's overall form during the season. Besides his two wins at Daytona and Fontana at the beginning the year, the five-car squad has remained winless following a 2008 season where it won 11 out of 36 races with victories from Carl Edwards and Greg Biffle.
"We're always trying to get better, we just haven't been able to do it," Kenseth said. "We're missing something, in my opinion, with the organisation to start with to make all of our cars faster because Carl hasn't won a race all year and he won nine of them last year.
"I think we need to really look hard at engineering and some of the stuff we're doing to make these cars run to start with, and on the #17 we need a little work, too. We've been inconsistent on pitroad. I've been inconsistent. I missed the pit box tonight.
"There are certain things I can do better as well, so we just need to evaluate the whole thing and try to get back to where it needs to be. The first year they had the Chase we had five of us in there and we just have to keep working at it."
Roush Fenway team-mates Carl Edwards and Greg Biffle were able to secure a place in this year's play-off despite having no wins thus far. They will start the title battle from ninth and 12th place respectively.
Kenseth had always been in the Chase for the Sprint Cup ever since the format was implemented in 2004, following his championship season. Reigning champion Jimmie Johnson is now the only driver who has made it into the series' play-off every year.
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