Jon Gruden's time in the NFL could be over for good ... so says Nate Burleson, who tells TMZ Sports he's "not sure" if the league will ever take the coach back.
Less than two weeks after the 58-year-old stepped down as head man of the Las Vegas Raiders due to crass emails he sent between 2011 and 2018 ... we asked Burleson out at LAX if he thinks there's any way Jon can get another gig in the league.
The wideout turned TV star acknowledged time does heal all wounds ... but he added he's just not sure if Gruden can rebound from the scandal -- given the racist, homophobic and misogynistic language he used in the online messages.
"The league is 75 percent Black and some of those words can be interpreted as racist, insensitive," Burleson said. "And, Carl Nassib is an openly gay player. And, the words that [Gruden] used when talking about Michael Sam, it really does hurt the heart to hear."
Nate added, "This is an inclusive league. And, I think that's what we pride ourselves on. I'm not sure if we'll see him back in the league. I'm not sure."
As for Gruden's claim that he made earlier this week that "the truth will come out" ... Burleson said, "There's some truth of his in those emails. Which is why it was so disheartening."
Jon has apologized for the messages -- saying he was "sorry" in his resignation statement -- and his close friends, like Andre Rison, have said they do not believe he's a racist or a homophobe.
Only time will tell if that's enough to convince another owner to give him another shot.