That muscle pull that happened midway up was more than a cramp, but less than a tear. It's fairly painful today, but I don't think it is a serious injury. I'm hoping a few days of resting it will allow it to heal.
On a side note... I gotta say it was a bit of an ego boost to school the other guy who is nearly 20 years younger than me. He, like me, had been on an extended break from DL, but he has pulled 475 before.