That’s not the No. 10 on the back of Ed Oliver’s jersey.

It’s a target.

Double- and triple-team blocks. All legal, all part of the strategy and gamesmanship to stop (or limit) one of the most disruptive and best players in college football.

Then there’s crossing the line when it comes to chop blocks.

Dirty.

Dangerous.

Cheap.

And illegal.

So why does it keep happening to Oliver, the University of Houston’s two-time All-America defensive tackle, Outland Trophy winner, Heisman Trophy candidate and possible No. 1 pick in the 2019 NFL draft?

“Malicious,” one person said after watching the video of Oliver’s taking a low block to the knee late during the Cougars’ 49-36 victory over Navy on Saturday.

In three seasons, Oliver has encountered so many questionable blocking techniques, specifically chop blocks — in which an offensive player blocks low on a defender who is already being blocked high — that his knees ought to hire a private security firm.

Two particularly low blocks stand out. Last season against Temple, Oliver suffered a sprained MCL in his left knee that limited him in four games. On Saturday, Oliver had to leave late in the fourth quarter with what was later diagnosed as a bruised right knee. Two Navy offensive linemen engaged Oliver, with television replays showing left guard Laurent Njiki coming from a side angle with a low block to Oliver’s right knee. No penalty was called.

UH coach Major Applewhite said Oliver will be monitored throughout the week and is questionable for Saturday’s game against No. 21 South Florida. The 6-3, 292-pound junior did not practice Tuesday and is listed as day-to-day.

AAC made aware of play

While the latest injury does not appear to be serious, what happens next time when Oliver might not be so lucky?

What happens when a knee blows out? If not Oliver, it’s bound to happen to somebody else.

What happens when it costs a potential top-five draft pick millions? Before this season, Oliver and his family took out a catastrophic injury policy.

At the end of last season, Applewhite, concerned for the health of his star, compiled about a dozen clips of low blocks and sent them to the American Athletic Conference office. At least four opposing teams have attempted to use low blocks on Oliver over the last two seasons.

And we’re not even talking about the number of holds on Oliver that go uncalled.

While not directly because of Oliver, the NCAA took steps in the offseason to make chop blocks illegal. Under the new rule, blocks below the waist on defensive linemen can come only in the tackle box “if the force of the initial contact is directed from the front.”

When reached Monday, Chuck Sullivan, the AAC’s assistant commissioner for communications, said the league does not comment on officiating. Sullivan said the protocol is the same for every school each week: If there are plays that a school wants clarification on, they send in clips for review and receive a response from Bryan Platt, the conference’s supervisor of football officials.

‘It’s a cheap shot’

“It’s a dirty play,” Oliver told Yahoo Sports in August. “It’s a play designed to take a player out. I’d never do it to anyone. It’s a cheap shot. I’m glad it’s illegal.”

He was not available to reporters after Tuesday night’s practice.

The NCAA needs to take its rule-changing power one step further. If there is doubt, make those types of infractions reviewable, just as is done for targeting. If it’s illegal, the same punishment should apply as the one for targeting: A player is immediately ejected and must miss a half of the following game.

That would send a message.

In the meantime, Oliver’s teammates defended him for what seems like a regular occurrence dealing with the controversial blocks.

“Very frustrating,” linebacker Austin Robinson said. “It’s not really fair. He can’t do anything about it.

“I feel for the guy because I know he wants to play. For him to leave that game that way is not fair.”

Oliver has five regular-season games left, and the West Division-leading Cougars are in position to reach the AAC Championship Game for a shot at a coveted New Year’s Six bowl.

Rather than join the trend of projected high draft picks sitting out the postseason, Oliver has said he plans to finish what he started with the Cougars.

He should be able to do so without fear of another dirty block.

joseph.duarte@chron.com

twitter.com/joseph_duarte