"I got tired of being second team and playing behind guys I thought I was equal to," Doolittle explains. "I've just been working hard and I've dropped 18 pounds to try to step up this year.
"I was 308 at the bowl game," he adds. "I feel quicker. I was really heavy on my feet and I wasn't used to being 300 pounds anyway. I want to play at 285 because lighter is better for me. Sen'Derrick (Marks) is only about 280. Mike Blanc is 280. Those guys are quicker so I felt like I had to get down."
Doolittle lost 18 pounds in just over two months and is enjoying his best spring since he arrived at Auburn. Now at 290, he has shown more quickness and the ability to play multiple positions in Will Muschamp's multiple defense.
"I was thinking about moving to defense end," Doolittle explains, "and coach (Don) Dunn was like, ‘What are you going to do if you lose all of this weight and you can't play end? What are you going to do then?' I said, ‘Coach, I'll come back with you and try to work hard like I've been doing in the past.'
"With me losing weight I feel like I'm better," he continues. "In certain defenses (3-4) I play the end spot and I can play the D-tackle spot instead of just playing the nose. I'm opening eyes at different positions, I guess."
The senior Opelika native came to Auburn as a highly-recruited fullback and defensive lineman, but things fell apart because of injuries before they even got started. Since he got to Auburn he has been playing catch up with his conditioning and learning of the defense, which hurt work ethic as well.
Doolittle is physically healthy and ready to help the defense as a senior, which has translated into more fun and a better work ethic on the practice field this spring.
"I came in on the offensive side of the ball and I had two surgeries coming out of high school. I had to miss my whole first year. My sophomore year was really like my redshirt freshman year. It was hard and it set me back. All of the other guys were ahead of me. They were doing coach Yox's (Kevin Yoxall) workouts while I was on the bike.
"I feel like I'm playing harder," Doolittle adds. "I've got to play harder to make them (Dunn and Muschamp) happy. If you're making plays you're having fun. If you're not making plays then you're out there miserable like you don't want to be out there. It makes everything go a lot smoother when you're making plays and coach is on your side. It feels good."
Doolittle and the Tigers will wrap up spring training on Wednesday at 4 p.m. with a scrimmage at Jordan-Hare Stadium.