It's a reference to American football. These are both positions. A running back is they guy who takes the ball from the quarterback (the one who throws the ball) and runs with it (the ball is handed off to him, the quarter back does not throw it to him). The blocker blocks the running back from players on the other team trying to tackle him. The running back stays close to the blocker so that the other team must get close to the blocker to tackle him and thus it makes it easier for the blocker to block them.
Be prepared, hehehehe, for the use of sports' analogies by American businessmen. Eg., A new product is being promoted. "We are going to have Winger carry the ball on this one." Or,[the guy who has the ball is the only player who can score] "Nobody is buying the new product. Let's cut the price by 50% and see if a Hail Mary will bring in a few customers. [When everything else has failed and time is running out you use desperate measures to win]. "Let's open up a new territory in the northwest. With Johnson in charge, he will lead the company in sales. It will be a tip in. [a tip in is an easy score in basketball]