The sharp shooters over at The Fast Lane Truck spotted a 2017 Chevrolet Colorado ZR2 prototype sporting what appears to be the heart of an oil burner.

TFL caught the ZR2 roving around the Colorado Rockies dressed in full camo, but sporting the ZR2's tell-tale aggressive off-road rubber and a jacked up ride height. But it's the ZR2's booty that demands attention.

The prototype can't hide its decidedly diesel exhaust pipe poking out from under the bumper's right side, meaning we could see the 2.8-liter four-cylinder Duramax diesel join the new 3.6-liter V6 over the ZR2's lifespan.

Rumors have persisted since the original concept was shown at the 2014 LA Auto Show that Chevy would offer a Duramax in ZR2 guise.

If the diesel does end up joining the ZR2's repertoire expect it to carry a $4,000 price premium over the 3.6-liter V6.