EAGAN, Minn. -- Sam Darnold will continue as the Minnesota Vikings' lead quarterback when training camp opens next month, coach Kevin O'Connell said Wednesday as the team wrapped up its final OTA of the spring.

O'Connell stopped short of projecting anything beyond that, saying he plans for a "competitive" training camp at many positions. The Vikings have three other quarterbacks on their roster: rookie J.J. McCarthy and veterans Nick Mullens and Jaren Hall.

"We haven't had to put out a depth chart or anything like that," O'Connell said, "but yeah, I would say Sam would be the guy I would look to based upon the spring he's had, and really where he's at in his career and his quarterback journey, and what he's been able to do coming in and [hitting] the ground running and taking advantage of a competitive situation."

O'Connell said he reminded all four quarterbacks that depth charts don't dictate the future, especially as Minnesota started four quarterbacks throughout last season. The head coach has seen improvements from all options behind Darnold, challenging them to stay prepared.

"I have total understanding that we only control so much in this whole thing, and that's what I've challenged the quarterbacks to do -- control what you can, which is your preparation," O'Connell said. "How detailed can you be? Can you stack good periods of practice together? Good days together? And before you know it, you're looking up and it's not about the camp you've had, but it's about your readiness to help the Minnesota Vikings win."

Darnold agreed March 12 to a one-year contract worth $10 million, one day after incumbent Kirk Cousins agreed to sign with the Atlanta Falcons. The Vikings knew at the time they would likely draft a quarterback, but they do not want to play McCarthy -- their selection at No. 10 overall -- until he is as close to ready as he can be.

Speaking to reporters Wednesday, McCarthy said he spent the spring focused on improvement more than competing with Darnold, Mullens and Hall. Close observers have noticed some strong throws, including a dart last week to receiver Trent Sherfield on the final day of mandatory minicamp, as well as some that bounced in front of receivers or sailed over their heads.

McCarthy said he understands "growth is not a straight line." He added: "It goes up. It goes down. It goes up. It goes down. But I'm trying to maintain that trajectory of going up and up. I feel like I'm on that. Just attacking every day with a growth mindset, and it's been doing me well so far."

Asked whether that makes it easier to accept mistakes he has made, McCarthy said: "I definitely get down on myself, just being the perfectionist that I am. But you have to [accept it]. They're inevitable. Failure is inevitable in sports. You've just got to learn from them and learn from those little dips and not be attached to them emotionally. That's what I've been working on."

The first two weeks of training camp, O'Connell said, will be about "really identifying and setting the stage for how we want some of these competitions to fairly play out." McCarthy said he "of course" wants to play as soon as possible but that the Vikings' arrangement has been "a blessing" so far.

"I grew up watching Sam Darnold my entire life," McCarthy said. "Being able to just sit there and watch him, watch Nick, watch Jaren ... it's not what they say to me, it's what they do. And just being a sponge and observing them and, eventually, hopefully, one day surpassing them. But right now, they're just phenomenal human beings who are sharing their wisdom with me, and I just can't thank them enough and can't wait for training camp."