Kaep was going to be a pitcher in baseball where he received several scholarships until Unitversity of Nevada (the only college) offered him a scholarship to play football. To say the guy has some "zip" on his throws is an understatement. During the Pats game they were clocking his throws at 65 mph. For a football that's crazy. He just needs to learn to take some off of it sometimes.
Doing a quick google search it shows Dan Marino could throw a ball between 60-70 mph.