The key to any offense being successful is the offensive line. What makes the O'Brien so unique is its ability to be successful with both small and large linemen. The spacing between the linemen create gaps which allow undersized players to be very effective when blocking. We refer to the linemen as the Center (C), Inside Receiver (IR) and Outside Receiver (OR). The spacing between the C and the IR is three yards. This space is shortened if the IR is unable to block A gap penetration. The space between the IR and OR is about 1 yard. When teaching the alignment, we tell our IR to get set and then hold out his arms. We tell the OR to then hold out his arms and the perfect position is when their finger tips touch (Figure 1).
The first position every player learns in the O'Brien is OR because it is the easiest to master. In the base plays, it does not require you to pull, you block down (B gap or second level) on all but one play (24). If the player is not a good blocker you can "Hammer" the FB (see Hammer alignment Figure 2) and have the OR block down on every play. I have had players who could not block to save their lives and we still had success by simply having them get in the way of the LB at the second level!
The IR needs to be the best blocker. He will have to insure there is no A gap penetration and he will need to pull to block the backside defensive end on most counters. He will also be making the line calls. The IR does not need to be the best pass catcher and we have had seasons where we do not even send him out in routes.
The Center is a key position in any offense but never more so than in the O'Brien. He is asked to make two different types of snaps depending upon the play called and should be a good pass catcher. He does not need to be the biggest player especially if he is tough enough to make the counter blocks and a good receiver. The base snap is aimed at the running back which means it is a snap the QB will catch as he is taking off parallel to the line of scrimmage. The other snap will be snapped straight back and is more like a traditional shotgun snap (Figure 3).
It can't be stressed enough how important the blocking is to the success of the O'Brien and how much time needs to be spent in practice on recognizing and adjusting to defensive stunts and blitzes. The focus of almost every practice should be on the snap to the QB and the blocking. In the next segment, attention will be turned to the types of blocking utilized on the base plays.