Wide receiver was supposed to be one of the Dolphins’ most competitive position battles of the summer. But the group has made more news in the early going by who isn’t playing than by who is.

An apparent leg injury knocked second-year wideout Clyde Gates out of action Monday, joining an already ailing Brian Hartline (calf).

“It’s no good to sit on the sidelines and watch,” Gates said, “but you have to take care of your body first. I can’t just go out there and hurt my hamstring again.”

There was no timetable on a possible return, but Gates did participate in the afternoon walkthrough.

With two of the returning receivers out, Chad Johnson, Davone Bess and Legedu Naanee were the first-team receivers in three-wide sets. Naanee was among David Garrard’s most popular targets.

“We certainly wouldn’t want to put any undue pressure on somebody if they’re returning from a medical situation that isn’t properly healed or dealt with,” coach Joe Philbin said.

In other injury news:

• Safety Chris Clemons was back in pads after missing the previous two days of practice with a bruised knee but was limited. Jimmy Wilson again took his place on the first-team defense.

• Fellow safety Kelcie McCray, a rookie out of Arkansas State, was not at the team’s walkthrough after leaving the morning session with an undisclosed injury.

• Defensive end Olivier Vernon appeared to tweak his ankle during contact drills but returned to finish the morning session.

No distraction

Less than a week into camp, the ubiquitous Hard Knocks camera crew is still a novelty for many. Just not for first-year defensive coordinator Kevin Coyle.

Why? He has been through it before in 2009 when he was the secondary coach of the Cincinnati Bengals.

“You can’t allow anything to be a distraction,” Coyle said, when asked what he learned in his first go-round. “In this league, there are going to be cameras on you each and every place you go. You have to focus on [your] job and you have to have singleness of purpose and focus of mind to go out there and not let anything get in your way.”

As for his defense, Coyle said there are multiple starting positions up for grabs, although he wouldn’t get into specifics. It had been assumed that the safety spot across from Reshad Jones was the only first-team competition, but Coyle indicated otherwise.

Tannehill works

Ryan Tannehill was in shorts and took reps mostly with the third string again, connecting on several well-placed passes when given time but occasionally struggling when not. He has earned high marks from his coach in his short time with the team, particularly for completing more than 40 of his 53 competitive snaps Sunday.

“We had a couple opportunities for some big plays early that we didn’t convert on, but for a rookie quarterback, I think he is doing very well,” Philbin said.

Tannehill will be allowed to practice in pads Wednesday, per league rules.

A day off — sort of

After four consecutive days of practice, players have the day off Tuesday — at least physically.

Although Philbin cannot mandate work beyond what’s allowed under league rules, he did make clear that he notices individual initiative — including some extra time in the hot or cold tub, or with the playbook.

“I told the team in the meeting, I don’t think you have to do it 24/7 to be great, but I think you have to have a commitment,” he said. “When you look up the definition in Webster’s of a professional, one of them I believe is an expert in a given field.

“If you want to become an expert at something … it requires a little extra sacrifice and a little more dedication.”