Josh Allen's Teammate Says NFL Star 'Is In Love' With Hailee Steinfeld

Josh Allen and Hailee Steinfeld are now apparently so serious ... one of the NFL star's closest teammates just said he believes the quarterback is "in love" with the actress.

Buffalo Bills left tackle Dion Dawkins broke it all down while appearing on Kay Adams' "Up And Adams" show on Tuesday alongside Taylor Lewan.

The 29-year-old offensive lineman -- who's great pals with Allen -- was talking about how the signal-caller famously split his pants in Paris last week ... when he insinuated the QB's obsession with Steinfeld led to the now-viral moment.

Dawkins explained that because he thinks Josh is so smitten with Steinfeld, he's been open to trying out a new wardrobe ... which culminated in the pants malfunction.

Then, he dropped the L-word into the conversation.

"You know your quarterback, man," Dawkins said. "And I know Josh, and I know Josh is not a product of his environment, but, you know, Josh is in love."

"Josh is in love," Dawkins continued. "So, if his girl is shopping and she's like, 'Joshee, try these on!' Josh is going to say, 'All right. I'll try these on!'"

Lewan's eyes got super big when "love" got thrown around ... but it sure doesn't seem like Dawkins was speaking in hyperbole.

After all, Allen and Steinfeld have been dating for around a year -- and while they've largely kept out of the public eye, they've seemed to spend a ton of time together. In fact, Steinfeld was seen traveling to L.A. this past December to watch Allen's game against the Chargers, before she jetted back to Buffalo to presumably spend the holidays with him.

Neither has publicly commented on the other much -- if at all -- but it sure looks like behind closed doors, a real-deal romance is brewin'.