Lamar Miller didn’t hesitate. The hole was there. So he hit it. Hard.

And a heartbeat later, Miller was in the end zone, proving — at least in shorts and helmets — that 218 pounds is plenty big enough to be an effective short-yardage back.

Of course, Miller hopes his role is far more expansive than that. The Dolphins’ second-year rusher doesn’t want any prefix attached to his title except one: every-down.

“Everybody’s mind-set is to start,” Miller said Wednesday after the day’s 90-minute organized team activities. “We’ve just got to come out here and compete every day and get each other better, so whoever gets into a starting position, just help this team win.”

Technically, the competition to succeed Reggie Bush as the Dolphins’ featured back is “wide open,” as Dolphins coach Joe Philbin said Wednesday. Daniel Thomas, Mike Gillislee, Jonas Gray and Marcus Thigpen also are in the mix.

But through May, Miller appears to have a leg up on the field, both in repetitions and in production.

He is taking the bulk of snaps with the first team, and when he does, he has been effective, showing the same explosiveness he did at the University of Miami.

“I think he’s just more comfortable,” quarterback Ryan Tannehill said. “He knows the offense. He’s been in it for a year. He knows the protections. Now he can just go out and let his athletic ability shine for itself.”

In March, before free agency began, the Dolphins sent out signals that they were ready to move on from Bush, who averaged more than 1,000 yards in each of his two seasons with the Dolphins.

On Wednesday, Philbin explained why.

“We liked the guys we had,” he said.

“We thought there was potential there. We thought there was opportunity for growth and development out of those guys, and we’ll see how that goes here in the next couple weeks and months.”

Philbin said that despite the open competition at this point, too much should not be read into who’s working the most with which unit. Instead, the springtime is about installation as much as it is evaluation, and exposing the players to as many situations as possible.

“We’re going to watch the tape and see how our players pick up the blitz, run routes, see how they run the ball when they have the opportunity and go from there,” Philbin said.