Ware has over 100 career sacks but has just six this season in an injury-hit year as his side continued to struggled on defense as they lost 45-28 to the Chicago Bears on Monday.
"Health-wise, I'm fine. I feel good, I was running around out there. I didn't get tired," Ware told ESPN.
"At the end of the day, I haven't been playing like the DeMarcus of the past and I got to get back to that.
"It's December (and) people always say the light turns on in December, and you set yourself apart from everybody and I got to get back on track with that."
The Cowboys dropped to 7-6 in their season and trail the Philadelphia Eagles by one game in the race for the NFC East title.