The Seahawks’ first day of camp was notable mostly for the guys who were not available, but there is nothing to worry about.

Tyler Lockett, one of three PUPs, failed his physical but will be back shortly. DeShawn Shead, who had a minor cleanup surgery on his ACL knee, was not expected anyway. Rookie Justin Senior is the other PUP.

Malik McDowell and C.J. Prosise were the surprising absences on Day 1, though not a big deal since neither is imperative to Seattle’s Super Bowl challenge.

Pete Carroll and John Schneider knew McDowell was a gamble when they drafted him — it’s why they traded down three times before picking him in the second round.

The big concern about the 21-year-old has been a lack of maturity and motivation. Now, after this ATV incident, you might add off-field judgment as a further worry. Whatever the story behind the accident, he’s certainly not off to a good start.

McDowell, who reportedly suffered a concussion and facial abrasions, says he will be back soon. But it really doesn’t matter. At this point, anything McDowell offers is a bonus. The Hawks think the 6-foot-6 second-round pick can be their version of Calais Campbell. But their defense won’t be any worse for not having him — because it has never had him.

It’s entirely possible that one of the four other players the Hawks acquired on the way to picking McDowell will end up a bigger contributor — this year and/or in the future. That quartet includes defensive backs Delano Hill, Tedric Thompson and Mike Tyson, plus running back Chris Carson.

The Seahawks’ other “anything he does is a bonus” baby is Prosise, who missed the first day of camp because he was “sick as a dog,” according to Carroll. Not a good start for a guy who barely got on the field as a rookie last season due to a string of injuries.

Carroll loves the guy and talks him up all the time (Prosise walked Carroll’s talk in two games last year), but Prosise keeps finding ways to stay off the field. He needs to get on it and prove he is no Jordan Hill — another promising third-rounder whose Seattle career fizzled amid injuries.

Speaking of draft busts, the Hawks are giving several guys second chances. Marcus Smith, a first-round pick by Philadelphia in 2014, became the latest former high pick to sign this year. He joins 2013 first-rounders Luke Joeckel and Dion Jordan, plus 2013 second-rounder Eddie Lacy.

Smith and Jordan are cheap gambles on once highly regarded pass rushers. Smith practiced at linebacker on Day 1, while Jordan was placed on the non-football injury list with an old knee injury.

Carroll said of Smith: “We see him as an outside ‘backer and a nickel pass rusher as well. He is a really good athlete, hungry to prove it. Whatever happened there (in Philadelphia), I don’t know. But he is hungry to prove it and was really excited about coming here.”

Carroll said of Jordan: “It’s going to be a bit before we get him back. … I’m hoping we will be able to do something before the end of camp.”

Joeckel, coming off a knee injury, reportedly worked mostly at left guard on Day 1, with a little left tackle throw in.

“We were very fortunate with Luke in the offseason. The way we adapted practice really helped him work throughout,” Carroll said. “He came out here really knowing his stuff. He is right in position to be a starter for us. We will see how that works out. We think he could start at guard or tackle. That is a great asset for us. He’s got experience; he’s been around. He is a heck of a football player and he is excited about being back and he is pumped up to add to this football team.”

The No. 1 O-line reportedly was as expected to start camp (L-R): George Fant, Joeckel, Justin Britt, Mark Glowinski, Germain Ifedi. Also as expected, second-round pick Ethan Pocic rotated with Ifedi at right tackle.

Carroll raved about Fant gaining 22-23 pounds to 319, calling him “fantastically strong and fit.” Of course, that’s a small part of playing left tackle. We won’t know a thing about his actual improvement until preseason games start and he is blocking live pass rushers.

The Seahawks made a couple other notable moves in the days before camp started, bringing back Marcel Reece (as many of us thought they would) and trading for Pro Bowl special-teamer D.J. Alexander.

We fully expect Reece to win the fullback job over Kyle Coleman and Tre Madden, although he will have to show well on special teams, too.

“(Reece) is very experienced and very versatile,” Carroll said. “He knows the system. He is a fantastic team member. … Marcel did a very nice job for us last season when he came in. Immediately, you can feel his experience, … but we will see how it goes and he will battle.”

The Alexander acquisition, in a deal that sent Kevin Pierre-Louis to Kansas City, seems like the Kelcie McCray deal in 2015 — Seattle once again getting a special-teams ace from the Chiefs.

KPL had great speed but could not stay healthy. It seems odd that the Chiefs would dump a Pro Bowl performer, but maybe they think KPL offers more upside as a linebacker.

In Seattle, Alexander probably will push Arthur Brown for the final LB spot.

“(Alexander) is a ridiculously good special-teams player,” Carroll said. “He has a big attitude and energy about him. He lit up the Pro Bowl with his efforts and flying around and he has just had a big impact on a team.

“I think we have done more to help our special teams this offseason than any offseason we have had,” Carroll added. “That is a very, very deep core group. It’s going to be very competitive, but we are really excited about it. We have never had as many guys that know how to play special teams.”

This is the fifth straight year Schneider has made a camp/preseason trade. In 2013, he acquired Sealver Siliga from Denver for John Moffitt; in 2014, he acquired Marcus Burley to help in a cornerback crisis; in 2015, he again tried to fortify the secondary with Mohammed Seisay and McCray; and last year he got Dewey McDonald from Oakland (another deal with the 49ers fell through). The deals for Burley, McCray and McDonald all worked. We’ll see if Alexander makes it, too.

Schneider might not be done making moves on special teams either. Blair Walsh reportedly has been very underwhelming since he arrived in Seattle. He missed field goals from 34 and 44 yards on Day 1, and it seems only a matter of days, if not hours, before Schneider brings in another kicker.