Trent Richardson, Paul Posluszny

Indianapolis Colts running back Trent Richardson carries the ball against the Jacksonville Jaguars during the second half of an NFL game in Jacksonville, Fla., on Sept. 21, 2014.

(AP Photo)

Running back Trent Richardson was coming off his best showing as a member of the Indianapolis Colts - a 79-yard effort against the Philadelphia Eagles on Sept. 15. But in keeping with his bedeviled career as a Colt, he spent the next week answering questions about his two fumbles - one recovered by the Eagles in their 30-27 victory - and his one-year anniversary in Indianapolis.

And yet the former Alabama All-American said he's having fun now in Indianapolis.

"It was fun last year," Richardson told ESPN.com, "but it wasn't to where it is at this moment. I can say I can really contribute to the team other than practice."

The Cleveland Browns selected Richardson with the third pick in the 2012 NFL Draft, and he rushed for 950 yards and 11 touchdowns as a rookie. But after two games last season, the Browns traded Richardson to the Colts for a 2014 first-round draft pick. In 14 games for Indianapolis, Richardson ran for 458 yards and three touchdowns, averaging 2.9 yards per carry.

"I finally got to see the downside of football," Richardson told reporters gathered at his locker on the one-year anniversary of the trade. "I've never been on the bottom, never not been the guy who's having the most success. All my life I have been on top in football. Never had to struggle at all. I got to learn a lot about me, a lot about my family, my real friends, my teammates. It was a humbling situation, not just for me."

After a year in the Indianapolis system, Richardson said he's comfortable. Last year, he was uncertain.

"I was confused," Richardson said. "I didn't know (the system). Now I do. I know what I need to do and where my eyes need to be. I know what my quarterback's talking about. I do know what my offensive line is talking about, and I can study the other team now. It ain't like I don't know."

Richardson was confused by something in addition to the Colts' playbook last season.

"The whole last year, I was wondering why I got traded, how did I get traded," Richardson said. "I felt like I was one of the best on the field (in Cleveland), and I felt like I was giving it my all. I just didn't understand."

Richardson followed his 79-yard showing against the Eagles with 57 yards in a 44-17 victory over the Jacksonville Jaguars last week. He did it on 14 carries, giving him an average of 4.1 yards per carry, his best in one game with the Colts.

Indianapolis coach Chuck Pagano said he understands why Richardson says he's having more fun.

"I think probably the biggest thing is when you have success, you gain confidence," Pagano said during a press conference last week. "He's not thinking out there. Right now, he's just playing the game. We are playing a kids' game. We talk about it all the time. That's all he's doing. He's not thinking; he's reacting. He's reacting to what his keys are telling him to do. When you have success, I don't care what you do in life, the more success you have, the funner it's going to be."

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The Colts have used Ahmad Bradshaw in relief of Richardson. The two-time 1,000-yard rusher missed almost all of last season with a neck injury, but has had success rotating with Richardson in 2014. Bradshaw had gained 150 yards on 25 carries, and three of his 12 receptions have gone for touchdowns.

Richardson said Bradshaw's abilities have helped the Colts broadened their options for running backs, which has helped him, too.

"A lot of my running has been through the middle since I've been in the NFL," Richardson said. "Now, I'm starting to get some outside runs, some draws, different stuff. They're starting to open up the playbook, especially with Ahmad. We can do so much with him. Even on third down, they give him most of (the snaps). They play both of us on third down at times. We're grinding and having fun at the same time this year."

The Colts host the Tennessee Titans for an AFC South game at noon CDT Sunday.