INDIANAPOLIS -- Indianapolis Colts starting cornerback Greg Toler has lined up across from countless receivers in practice during his seven-year NFL career.

Larry Fitzgerald. Reggie Wayne. T.Y. Hilton.

So lining up across from first-round pick Phillip Dorsett would be just like going against the receivers listed above.

It wasn't the same.

Ball security has been a focus for rookie receiver Phillip Dorsett during training camp. AP Photo/Michael Conroy

Toler and Dorsett were on the outside racing down the field when the veteran cornerback took his speed to “fourth gear” to try to stay with the speedster out of the University of Miami.

What did Dorsett do to make sure he could get by Toler?

“All of a sudden he dropped it into seventh gear,” Toler said. “I was like, ‘Wow.’ I had to tell him to slow down. He flat out burns down the field. You sit on his routes too much or miss on a jam and it’s a foot race.”

Speed. Exceptional speed, in fact (4.2-second 40-yard dash).

That’s the reason why the Colts went against what many thought they should do by taking Dorsett over an offensive or defensive lineman with their first-round pick back in late April.

Who cares that Indianapolis already had Hilton, Donte Moncrief and Andre Johnson on the roster. The Colts wanted more speed. And that's what Dorsett has given them so far.

Dorsett didn’t disappoint in his first preseason game. He had four receptions for a team-high 51 yards while starting with Johnson in the Colts’ loss to the Philadelphia Eagles last weekend.

But as Dorsett sat shifting his phone back and forth between hands on Monday, he didn’t have much interest in talking about his receiving yards. Losing a fumble was more important to him.

“I don’t look at things like how many catches I had and things like that,” Dorsett said. “I look at what I can improve on. Fumbling is definitely one of the things I can improve on. I have to learn from it by working hard in practice on my ball security.”

Colts coach Chuck Pagano echoed Dorsett’s words.

“He’s a big play waiting to happen, but again, he has to take care of the football,” the coach said. “You’re looking at a guy that’s going to be an outstanding football player. But you know, what you’re going to remember is the turnover. He’s going to be a dynamic guy for us.”

Dorsett, according to the people I talked to, has been a sponge since he reported for rookie minicamp back in May. He’s been that way with the coaching staff, quarterback Andrew Luck and especially Hilton and the veteran Johnson. Dorsett really had no choice but to be a sponge because the Colts plan to line him up and use him in an assortment of ways this season. He can line up in the slot, on the outside, come in motion and take a reverse. He's also the primary punt returner.

That’s just how skilled Dorsett is.

“He’s a fast study,” offensive coordinator Pep Hamilton said. “One of the things that’s been surprising about Dorsett is his ability to digest a lot of information and be able to play multiple positions in our offense. It’s always been a challenge for a lot of young players to be able to come in and handle the volume that we put on them. He’s done a pretty good job.”

Dorsett’s ability to grasp concepts quickly came after he made the switch from quarterback to receiver his sophomore year in high school. The switch came once he realized he was too short to play quarterback.

“When I want to apply myself to something, I’m really good at learning it,” Dorsett said. “The hardest part is knowing what position you are at one moment and then somebody else coming and you’re going to a different position and your whole mindset has to change to run a different route and all that. You have to be on your toes because you never know what position you’re going to get.”