As Denver looks at how to use their RB depth, let's take a brief look at the different ways that teams use RB depth. Each has advantages and disadvantages, and one isn't really the "best" way to go. It's a matter of what the team has available. Today we'll focus on roles of a RB with respect to depth (not roles in respect to player talent, like "power" or "speed"). These depth roles include primary, spell, change of pace, and rotational.
I figured this very short article would be good because we are focused on camp right now (and Guru's great updates), and because battles for depth positions are key right now. Enjoy!
The advantage to having a primary back is that a team has a back they can count on to play most downs in a game, and to excell in his position. The drawbacks is that he costs more, and if he goes down there is rarely someone good enough left to take his place.
Teams like Denver have the advantage of a system that negates the need for a primary back. If a RB goes down, any one cut runner can be put behind the zone block OL and do a credible job. In Denver's case, credible means a 1000+ yards season.
A spell back is used mostly with a primary back. If the RB tires out, the spell comes in to give him a break. Often, the number one consideration for a spell back is to just not give away the ball. When Mike Bell came in as a spell last year and fumbled, he committed a cardinal sin.
Change of Pace
Some folks look at this role as an insult to a player. It's not. It's a key role filled by a specialist. A change of pace RB is typically a power guy that is brought in for short yardage situations (remember the Bears and the Fridge?).
In other systems, especialy committee back systems, a power RB wears down the defense, and a speed specialist is brought in to tear up the field. Often the fans see the exploits of the speed back, and demand that he plays a greater role, forgetting that it was the power back who made the long, flashy run possible by wearing down the defense.
A rotational back is one of two backs that trades equal time as a starter. In coach speak, the second player on the depth chart is called the rotational (even if he is on an equal footing with the #1).
The criticism of using rotations is that the team must not have a back good enough to be a primary back. This may or may not be fair, depending on the system. Rotationals extend the playing life of a RB, and keep the RBs fresh. It also makes scheming by the defense more difficult. It's downside is that a RB may not get into a "rhythm" during the game.
As always, fire away with any questions on this, or any other subject relating to the great game of football!