Rewatch the game, and you will see on MOST of Pead's carries someone coming UNBLOCKED either off the edge, of simply being "missed" to make the tackle.
Fisher made a comment regarding the FIRST play of the game, that if a certain WR makes his block, Pead (Fisher's words, not mine) "may have scored"! Go back and watch the play, and see Pettis looking for someone to block, and they guy he runs right past, makes the tackle.
On the SECOND play of the game, C. Matthews comes UNBLOCKED (as both Cook and Pettis run right past him to block the SAME GUY on the second level). He crashes down the LOS and makes the tackle for a 2 yard gain.
On the very next carry, Pead makes one move and the CB, crashes UNBLOCKED (by Givens) into the backfield and makes the tackle for a 2 yard gain.
On the Draw play, once again, UNBLOCKED from the edge, Cook and Pettis leave Hyde UNBLOCKED and he almost takes the handoff form Bradford.
Later, (11:57 left in the 2nd Qtr), Pead makes a nice jump cut, and Pettis (who had gone in motion), gives a TOKEN brush block to the OLB (Nick Perry) and then looks as if he is running a pass pattern, ON A RUNNING PLAY, only to have Perry crash down the LOS and tackle Pead after another minimal gain.
You can way what you want about Pead, but there aren't many RBs in football who are going to gain yards when guys come UNBLOCKED and get a clean shot IN THE BACKFIELD.
These are all things that will get addressed as they get closer to Sept 8th. But from what I can tell, they just haven't put in the time in the RUNNING GAME yet, given they just haven't been in FULL pads throughout the early weeks of camp. Expect this to change very soon.