Between the two choices, it's MacCallum. Not even close. When Theismann got hurt you cringed, but at least you know "well, he broke his leg". With MaCallum, you didn't know how much he broke/tore/shredded, etc. I heard he was minutes away from losing his leg.
Second worst sports injury I've seen (among the 4 major sports), trailing only a certain Western NY netminder and memorabilia subject