Johnny Manziel -- Hot Girlfriend Scores Modeling Gig

Johnny Manziel's career might be in idle ... but his super hot GF is crushing it -- scoring a modeling gig with a clothing company ... TMZ Sports has learned.

Colleen Crowley just inked a deal with a brand called No Rulez NY -- which makes hats, shirts, sweaters, etc. -- and she's already knocked out a photo sesh featuring some of the items.

The man behind the company is 19-year-old Brian Wolfe -- who says he met Crowley through a mutual friend earlier this year and thought she'd be a perfect fit for the brand.

So far, the decision to sign Crowley is already paying off ... with not only Manziel sporting the gear, but Browns teammate Donte Whitner has also been seen rockin' the clothing out in public.

Wolfe says he does not have a deal with Manziel but hopes he can work out a deal with 35 in the future -- "I’m such a fan. He’s such a motivator for kids to make it and become successful. It would be an honor if he’d endorse it."