Mike Tomlin Upset With NFL's Lack Of Diversity, It's 'Disappointing'

"It was a disappointing hiring cycle for someone who watches it like I do."

That's Pittsburgh Steelers coach Mike Tomlin responding to the NFL's lack of diversity in its head coaching ranks ... and yeah, dude clearly ain't too happy about it.

Remember, the NFL's annual league meetings were last week ... and the teams put most of their head coaches proudly on display -- but there was one problem ... the black representation was tiny.

Of course, Tomlin missed the photo ... but so did 5 other white coaches -- which only highlighted an issue Mike says the league needs to address sooner rather than later.

"It was a disappointing hiring cycle for someone who watches it like I do," Tomlin told the Pittsburgh Post-Gazette ... "knowing some of the deserving men I do who I thought should have gotten an opportunity and didn’t."

"But we’ll continue to work and fight for equality and opportunity.”

The NFL fired 8 head coaches this past season -- including FIVE African Americans -- but only hired one black coach (Miami's Brian Flores) when replacing them.

That leaves the league currently with just THREE total black coaches ... and that's something that has Tomlin searching for answers.

"We’ll continue to fight for [equality within opportunity], not only in terms of head coaching searches, but maybe other areas of the profession as well."