For teams without a great deal of blocking strength, it's often valuable to hire a larger and more robust player to absorb - and deal out - more damage. For teams who already are powerful blockers, the addition of a ten-foot juggernaut is the icing on the cake.
"Big guys" come in almost all shapes, and all sizes from large upwards. The type of creatures commonly seen varies from team to team, and some races - most elves, for instance - prefer not to use them altogether. Nonetheless, big guys are always in demand. Consequently, their services come at a high price, particularly when it comes to the food bill, and the upkeep on a "big guy" is often more twice that of a smaller player.