By MARK LONG JACKSONVILLE — Jacksonville Jaguars quarterback Trevor Lawrence was carted off the field after taking a violent elbow to the facemask from Houston linebacker Azeez Al-Shaair that prompted two sideline-clearing scuffles. Lawrence was scrambling for a 6-yard gain on a second-and-7 play in the second quarter. He initiated a slide before Al-Shaair raised his forearm and unleashed on the defenseless quarterback. Lawrence clinched both fists after the hit — movements consistent with what’s referred to as the “fencing response,” which can be common after a traumatic brain injury.