Happened in the match where Zombielike clashed against Cruel Clown Coalition:

Bokor had just broken through the lines with the ball and going for it to the endzone like the wind. Nothing to stop him but himself... and he tripped. Elves rushed back towards their end zone and fouled Bokor knocking him out.

Ribald was knocked down in the midfield by the angered gang of zombies and Dragger put the boot in giving Ribald a serious concussion.
The team apothecary rushed to the scene and did a thoroughly rushed job stabilizing Ribald's condition permanently. As in no life signs.
"Crappy player... good riddance!" was his coach heard muttering.

The corpse of Ribald was dumped near the knockout box where Bokor was waking up. Perhaps that is why he was scavenged and raised to fill the ranks of Zombielike.