Michael Irvin says he's straight-up upset the Dallas Cowboys have low COVID vaccine rates ... explaining he believes it's a sign his former team doesn't really care about winning.

The Hall of Famer broke it all down at a recent charity event this month ... ripping the 'Boys for being below the NFL's 85% vaccine threshold.

"If you're not one of them teams [at the threshold]," Irvin said, "are you really thinking about winning a championship?"

As you may know, 85% is the number the league has set in order for teams to be able to ease COVID rules and regulations for the 2021 season ... and the Dallas legend is clearly pissed the Cowboys have yet to make it there.

Irvin went on to say Cowboys players should also be pissed that they're still below the 85% mark ... explaining the team should be doing everything in its power to get others to take the shots.

"Not being one of the [85% threshold teams] says there's other things to a great number of people on this team that are more important than winning championships," Irvin said.

"And that makes me worried."

According to multiple reports, only 13 of the 32 NFL squads have hit the league's required mark.

Of course, it really is a big advantage in the NFL this season to make it to that milestone ... teams who are above the threshold will be able to work out and practice way more freely than teams who are below it.

Irvin clearly understands this ... and is imploring the Cowboys to get above the mark ASAP.

"It should upset them," Irvin said. "Dude, you're not thinking right. You're not thinking right. Whatever you got, I don't give a damn."