Patriots take another hit on the edge with injury to top draft pick Rivers

Derek Rivers was taking part in a kickoff drill during Wednesday's joint practice with the Texans when he went down with an apparent knee injury. When the rookie third-rounder out of Youngstown State tried to plant and change direction, his left leg seemed to buckle underneath him, and he went down quickly.  After having his leg checked by head trainer Jim Whalen, Rivers walked back to the Greenbrier Sports Performance Center under his own power but with a noticeable limp alongside Whalen and head team physician Dr. Mark Price.  SCOUTS' VIEW Who's the more overrated Patriot? Rivers did not join his teammates on their trip to Houston for Saturday's preseason game. He made his way back to Boston