METAIRIE, La. -- Kenny Vaccaro said he felt like he let his teammates down when he was suspended over the final four games of the season due to a positive test for Adderall.

Especially since the New Orleans Saints safety said he was probably having the best season of his four-year career.

"To be honest, I just made a mistake," Vaccaro told ESPN in his first interview since the suspension.

Vaccaro said he did take Adderall, which is a stimulant banned by the NFL without a proper prescription. But he insisted it was not any kind of performance enhancer. He said he took it during the bye weekend as a pick-me-up when he was in Dallas to watch his former school, Texas, and his little brother Kevin play against Oklahoma in the Red River Rivalry.

"I was just tired and I really wasn't aware of the whole rule thing. The game's early in the morning, the state fair was going on," Vaccaro said. "I never took it before. I just did it, and it was just a dumb mistake by me, to be honest. And then I came back in Monday and had a random PED test. But that's the rules, and I take full responsibility.

"It wasn't worth it to get a little bit of energy to watch a game to come back and get a random PED test on a Monday. I mean, people can say it was unlucky, but I shouldn't have done it in the first place. But I don't take it, I don't have any problems. I just wanted to be up and alert. I don't take Adderall ever."

Kenny Vaccaro was having the best season of his career before getting suspended. Wesley Hitt/Getty Images

Vaccaro said coach Sean Payton and all of his teammates were very supportive and nobody made him feel like an "outsider." He even stayed in touch with many teammates, reviewing plays and situations that he saw on TV while watching from back in his hometown of Brownwood, Texas.

"I'm glad I had such a good locker room to be around," Vaccaro said -- though he said Payton's message to him was basically that the game doesn't stop to wait for anybody.

"He said, 'This is how this league is. As soon as one person's out, it just keeps rolling.' And it'll blow you away, just the magnitude of it. The train never stops for no one," Vaccaro said. "And that's the biggest thing I got from the whole suspension is that I'll never let this happen again. I felt like I let my teammates down. I thought I was playing at a really high level the last five games before I got suspended. Probably my best year, and I only played 11 games, statistically.

"I just feel bad, because I feel like was on a roll right before I got suspended and I just wanted to see how it would have all played out if I would've gotten to play the whole season like last year.

"And I was really hurt because I felt like we could've made a run, and I feel like I really could've helped the team in a lot of ways."

It's hard to imagine many Saints who are more excited to turn the page to 2017 than Vaccaro, who has already been training at the Proactive sports performance facility in Southern California. Vaccaro said he plans to spend the next few months there, training with other NFL players and draft hopefuls represented by his Athletes First agency.

The suspension was a disappointing setback for Vaccaro, who admittedly had to learn how to overcome some maturity issues earlier in his career -- or as he and coaches put it, "be a better pro."

Vaccaro's career has been loaded with highs and lows. He was drafted in the first round in 2013 and finished third in the NFL's Defensive Rookie of the Year voting but also suffered a broken fibula at the end of that rookie season. Then he struggled in 2014 and was temporarily demoted late in the season before bouncing back with a very good 2015 season and an excellent 2016 campaign.

Vaccaro's versatility as a strong safety/nickel back/pseudo-linebacker was a big part of the Saints' return to a three-safety alignment in 2016. He forced a career-high four takeaways (two interceptions, two forced fumbles) and assisted on another forced fumble in a critical moment during a come-from-behind win at San Diego. Vaccaro ranked second on the team with 67 tackles at the time of his suspension, had one sack, eight quarterback hits, five tackles for loss and five pass defenses.

"[Defensive coordinator Dennis Allen] just did a great job of, you never really knew where I was gonna be," said Vaccaro, who said he concentrated on getting a bit leaner last offseason. "I was able to be disruptive a lot more than I have in the past. Eleven games, I had better ball disruption than I did since I've been in New Orleans."

Vaccaro is equally encouraged by the progress of the Saints' defense as a whole.

They made some modest gains in 2016 after two lousy seasons in 2014 and 2015. They finished 27th in the NFL in yards allowed but were 10th over a seven-game stretch from Week 10-16. Their run defense greatly improved, as did their red-zone defense.

"I hate to be like ... I don't want to repeat myself, because we said last year was a different team. But this truly is," Vaccaro said. "And I think this is the first year the statistics actually prove that we're a better team."

However, Vaccaro said it was tough to see the Saints fire defensive assistant coaches like Joe Vitt, Bill Johnson and James Willis. But he said everyone from coaches to players understand that winning is "what keeps you in this league."

"Joe, he treated me like a son. He called me Sonny for [former Nike executive] Sonny Vaccaro. That hurt me, man," Vaccaro said. "But I mean, they always talk about it, winning is the only thing that matters, and how productive you are. Coaches and players.

"But it's just sad that had to happen, man. It will be a little different in the building not seeing those guys and the jokes they would make and the foundation and the culture we built."