Big Sean -- RIPPED By Sports Fans ... Over Football-Themed Music Vid

Big Sean is taking some serious heat over his new football-themed music video -- ripping the rapper as a clueless fake sports fan ... after he showed a wide receiver wearing #77!!!

The video in question is "I Don't F**k with You" -- which is set in a high school football stadium and features Big Sean as the star quarterback.

Which brings us to the first issue ... he's wearing #88 ... which is NOT a typical QB number.

It gets worse ... the wide receiver on Sean's team is wearing #77 ... a typical lineman's number.

There's more ... Kanye plays a coach wearing a mock turtleneck (who does that?) -- and people are also upset that players are chugging Red Bull on the sidelines instead of Gatorade or water.

Here are some of the comments floating around on Twitter ...

-- "crazy how that big sean video ruined football, red bull, and the phrase "on fleek" in less than six minutes"

-- "IDFWU video. If you love football it'll make you mad cause Big Sean is a QB who's number is 88. And a receiver number is 77."

-- "Big Sean don't know anything about football smh how you a quarterback and you number 88? Lol n the receiver 77?"

-- "@bigsean why is #77 running a fly route?"