EAGAN, Minn. — At one point during his first press conference of training camp, John DeFilippo was asked if he thought the wide receiver group would be the most scrutinized position battle over the next month.

The Vikings offensive coordinator downplayed that idea, noting that he expects competition at all spots on the offensive side of the ball.

But DeFilippo did spend a good portion of his presser chatting about a trio of wide receivers — Stacy Coley, Jake Wieneke and Brandon Zylstra — who are already in camp and who could push for roster spots.

DeFilippo said he was impressed with Coley before the wide receiver was injured in spring drills.

"It was good to see Stacy back out there [Wednesday]," DeFilippo said. "He had a couple really nice second-level releases yesterday, and we're looking forward to him having a big camp.

"He needs to continue what he was doing before he had the injury in the spring, because he was doing some really nice things for us," DeFilippo added.

Wieneke, a Maple Grove native, drew praise from DeFilippo for his football IQ and ability to catch the ball.

"Jake is just a really smart guy. He's assignment perfect. Very rarely does he have a mental bust. He's running good routes," DeFilippo said. "For a guy that's a big guy like that, you have to be assignment perfect and route perfect to use your body and be able to get open and lean on people."

Zylstra, another Minnesota native, also impressed DeFilippo this spring. But his real test will come next week when the Vikings don the pads for practice.

"I'm really looking forward to seeing that next step from Brandon, in terms of putting the pads on," DeFilippo said. "Obviously we have no pads on in the spring, we have no pads on here right now, so guys like Brandon that don't have a lot of experience in the NFL, along with our rookies and some of our other young players … I'm looking forward to them when we're getting press coverage, when we're moving around a little bit."

Here are four other takeaways from DeFilippo's podium session Thursday:

1. Remembering a friend

DeFilippo opened his press conference with heartfelt words for Tony Sparano, who passed away suddenly on Sunday at the age of 56.

Besides working together for the past few months in Minnesota, the two were also in Oakland in 2013 and 2014. DeFilippo recalled fond memories of his time with Sparano.

"He emulated everything you want in a person and as a coach," DeFilippo said of Sparano. "First off, he was a great husband, a great family man, a great grandfather.

"And as a coach he just took pride in his job and took pride in his relationship with his players, and was really a joy to be around every day. I was very lucky to call him a friend," DeFilippo added. "My thoughts go out to his wife Janette, who is very close with our family and his kids. We are going to miss our friend very much."

DeFilippo recalled a moment during the 2014 season that stood out to him. The Raiders were 0-10 entering a tilt on Thursday Night Football against Kansas City, but Sparano led his group to a 24-20 win on national television over their division rival.

DeFilippo beamed with pride again Thursday when he talked about the win and how much it meant for Sparano.

"Tony and I kind of gravitated toward each other from the start. We're both East Coast Italians, we know a lot of the same people, and we grew up the same way," DeFilippo said. "We both take the game very, very seriously. I think when you have those qualities, you have a tendency to gravitate toward those people.

"I just remember being so happy for Coach [Sparano] that night, because not only was it a nationally televised game against Kansas City, a Thursday night game, but Coach had inherited a really tough situation and handled it as well as probably anybody out there in the National Football League could handle it," DeFilippo added. "I just remember being so happy for not only our football team, but for him because he had stayed so consistent to what he believes and that it finally paid off."

Sparano's memorial service is set for Friday. The Vikings canceled practice so the team can attend the service.

2. Praise for the youngsters

Roughly half of Minnesota's 90-man roster is at camp right now, with veterans scheduled to report Friday and practice Saturday.

Those who are here include rookies and other younger players, and DeFilippo is impressed with where they are with regard to the steep learning curve of the NFL.

DeFilippo noted that Wednesday's practice, the first of training camp, was crisp and well-executed.

"It's such a whirlwind to many of these players coming from the combine to the draft to visits and all of those things where finally they have an opportunity to play football here," DeFilippo said. "I am not sure how much they were actually able to retain.

"What I was more proud of was when we went out yesterday and had very few mental errors, so that tells you that our rookies did a good job and were able to stay up with the information this summer and making sure they take pride in their job," DeFilippo added.

3. Extra attention for the quarterbacks

The only position group that has full attendance at the moment are the quarterbacks, where Kirk Cousins, Trevor Siemian, Kyle Sloter and Peter Pujals are at practice and walk-throughs.

DeFilippo said he prefers having all of the signal-callers in camp early so that he can work closely with the group before everyone arrives in town.

DeFilippo said the extra time allows him to break down additional details as the Vikings continue to install and learn his offensive system.

"I think it is great for Kirk and great for all of the quarterbacks to be here," DeFilippo said.

"We are so time-limited in the spring when installing a new offense, and now it was just rush-rush-rush," DeFilippo added. "We are so time limited with the players, and now we can get into the nuts and bolts of what you are trying to do."

4. O'Neill bulks up

Shortly after being drafted in the second round by the Vikings a few months ago, Brian O'Neill said one of his main goals was to get in the weight room and add to his 6-foot-7 frame.

According to DeFilippo, the Vikings rookie offensive tackle appears to have done so since minicamp ended.

"I think [Brian] has gotten stronger over the summer," DeFilippo said. "I think I saw him anchor down yesterday, which is better. When I say anchor, I mean he was able to stymie the defensive end at the line of scrimmage.

"I saw better combination blocks out of him and [guard Colby] Gossett on the right side yesterday," DeFilippo added. "I think it's just the combination of getting those reps in the spring has really done him well, carrying over from the spring."