KANSAS CITY, Mo. — Justin Houston was a bit late to practice over the weekend because he had to take one of the league’s random drug tests, and the star linebacker wasn’t told about it until he’d just gone to the bathroom.

His brief absence still caused quite a stir on social media.

If nothing else, the humorous episode showed just how closely watched the linebacker position will be in Kansas City this season.

The group anchored by Houston, veteran stalwart Derrick Johnson and breakout pass rusher Dee Ford could be one of the best in the league if everyone stays healthy, and could ultimately hold the key to whether the Chiefs have a defense that can carry them deep into the postseason.

“This year we are healthy. The main guys are healthy from the start,” Houston said. “Last year from the start we didn’t have everybody. This year we have everybody from the start, and if we can just keep everybody healthy I think we definitely can make a lot of noise.”

The Chiefs often struggled to pressure the quarterback and stop the run last season, and that was a direct result of the difficulty they had in finding able bodies at linebacker.

Houston struggled with a knee injury for the second straight year last season. Johnson ruptured his Achilles tendon in December. Tamba Hali has become a part-time player thanks to his age and injuries. And backup linebacker Josh Mauga went on injured reserve in training camp.

The shuffling of replacements dragged down the entire unit. The Chiefs only piled up 28 sacks after getting 47 the previous season, and that created problems elsewhere on the defense.

Now, it appears the Chiefs’ linebacker group is the healthiest it’s been in quite a while.

Houston is running with the first-team defense in 11-on-11 periods in training camp, and Johnson is already back to full speed after his knee surgery. Hali is on the physically unable-to-perform list, though that was expected as the Chiefs try to keep him fresh for the regular season.

“I’ve had some good luck and I want to keep it going,” said Johnson, the franchise’s career tackles leader, who also ruptured his other Achilles tendon a couple of years ago.

“It’s 7 months removed from surgery, so it’s a little different,” Johnson said. “It’s good to get out here and knock off the cobwebs and get my feet wet. Mentally I’m almost there all the way already, but physically I’ll get a little faster during camp.”

Hali also said he’s “way ahead of the ballgame.”

“Last year around this time, I could barely run. It took a while for me to regain my strength,” he said. “As far as where I am today, I can run. I can do the things that I was doing before the year. I feel much healthier. …

“It’s a little different because of my age and the amount of snaps I’ve gotten. But again, that doesn’t play in my mind, just because I am a competitor.”

Despite their core of veterans, the Chiefs are being pragmatic about the linebacker position. They saw how injuries mounted last season and quickly learned the value of depth across the board.

That’s why they signed Mauga as a free agent, and traded special teams ace D.J. Alexander to the Seahawks for linebacker Kevin Pierre-Louis last week.

It’s why they grabbed Reshard Cliett off waivers from the Titans and drafted Ukeme Eligwe in the fifth round out of Georgia Southern.

Throw in holdovers such as Justin March-Lillard, Ramik Wilson and Terrance Smith and there are plenty of bodies in training camp, each competing for playing time in what could be a stacked unit.

“Obviously, we missed Justin for quite a while,” Chiefs defensive coordinator Bob Sutton said after practice Monday. “Obviously, he is a really good rusher. We had some nicks and knacks with injuries and that, but that’s kind of the NFL. It’s what everybody goes through.”

It’s also what prompted Chiefs coach Andy Reid to state the obvious: “We want to keep building the depth in that position.”

And if everyone stays healthy? Even better.

“We have a big window of opportunity for us,” Ford said. “You don’t want to think ahead, but you still want to think about that. We’ve been to the second round (of the playoffs) and then last year we had the first-round bye.

“We want to get to big plans. We’re definitely coming into this year, chopping wood each day, but also thinking of where we’re trying to end up.”

NOTES: The Chiefs waived WR Antwan Goodley and TE Emmanuel Byrd and signed WRs Corey Washington and Robert Wheelwright after practice Monday. Washington has not appeared in an NFL game since 2014, when he was with the Giants. Wheelwright went undrafted out of Wisconsin this past offseason.