Mike Zimmer is one of the only NFL head coaches to call defensive plays, but after three seasons with the Vikings he's considering delegating those duties to defensive coordinator George Edwards.

Zimmer hasn't yet decided and could have Edwards take a preseason game later this summer. Edwards called the defense when Zimmer missed the Vikings' 17-15 loss to Dallas last season.

"I've thought about it more this year than I ever have," Zimmer said Thursday as the Vikings ended a three-day minicamp to close the spring. "If I did that, I think I'd be able to interject a lot."

By lessening his grip on the defensive reins, Zimmer said he could spread his attention throughout other parts of the team. Zimmer inherited one of the league's worst defenses in 2014 and the Vikings have since ranked 11th, fifth and sixth in points allowed.

Zimmer said he is still tussling with how much more he should delegate on defense.

"I've always felt one of my best traits was on Sundays," Zimmer said. "When one of these great quarterbacks has the ball, figuring out ways to stop him."

The offense has been a different story. The Vikings have ranked 20th, 16th and 23rd in scoring the past three seasons, and Zimmer said he has spent more time in meetings with offensive linemen this year than in previous offseasons.

"That's part of my mentality, is continue to grow as a head coach," Zimmer said. "Continue to be involved with the defense but be a lot more involved in the overall — offense, special teams than I have been before."

Focus fell on red zone

The Vikings were dreadful offensively and mediocre defensively when approaching the goal line last season, so they emphasized the red zone this spring.

Zimmer orchestrated more sessions inside the 20-yard line during offseason practices, shifting the focus from third-down situations to hurry-up and short-yardage modes. Only the Jets scored fewer points per red-zone trip than the Vikings did last season, according to Football Outsiders.

"We've got to be better," quarterback Sam Bradford said. "We've got to be more efficient. When we get down there, we've got to score touchdowns and can't settle for field goals. I think trying some new concepts down there, some things we did well last year and trying to find a balance. Maybe add a few new plays down there."

Good news for Zimmer

Zimmer had a checkup with his doctor Wednesday and was told the retina in his right eye is "perfect" and the pressure is "great" about a month after his eighth surgery.

The 61-year-old coach doesn't have any more operations planned. His vision is progressing, currently at 20/100 with correction while the gas bubble holding his retina in place continues to dissolve. He was told there's a "one-in-five" chance he may experience issues with his other eye at some point.

"He said he'd be absolutely shocked if anything else happened to this [right] eye the way it is now," Zimmer said. "I'm just about out of the woods."

Floyd on second team

Veteran receiver Michael Floyd has taken part in 13 practices with the Vikings and almost every rep came with the second-team offense behind Laquon Treadwell.

Floyd, 27, still has strides to make in the offense, Zimmer said, but Harrison Smith, Floyd's former Notre Dame teammate, liked what he saw from Floyd this spring. Floyd is likely facing an NFL suspension to start the season after his extreme drunken driving arrest last year.

"He looked like the Michael Floyd I've always watched," Smith said. "He was making plays, going up and getting balls and blocking."