And each of those positions has multiple roles to play. The "A" backs are quick runners who also must be relied upon to run routes out of the backfield. The "B" backs are somewhat larger players whose blocking ability will be tested more frequently, but also must be capable of running with strength.
Thus, it comes as little surprise that Gillespie was a busy man at practice Tuesday. He led drills focused on many different fundamental skills in rapid succession.
It started with a bit of route-running work. The "A" backs lined up close to a slot receiver position and went in motion. Quarterbacks Geno Smith and Paul Millard alternately took reps, taking a quick step back after the snap before turning and firing a short screen pass.
It sounds simple enough, but there was much technique to be mastered, which was perhaps one reason why head coach Dana Holgorsen was watching intently. Holgorsen corrected several players for turning upfield too early before seeing fit to stop the drill and explain the point in a bit more detail.
"Let the ball take you upfield," the head coach instructed. "Don't go upfield before the ball gets there." Holgorsen went on to explain that the early move made it tough for quarterbacks to determine where to throw what is a difficult pass that requires a lot of touch -- by waiting until the ball was in the air to move upfield, quarterbacks could more quickly and easily understand how much to lead the intended receiver into the route.
Notably, it was freshman running back Dustin Garrison who Holgorsen singled out as the only player he had seen execute the proper technique to that point. But after Holgorsen's demonstration, more and more players seemed to catch on.
"It's that easy, guys," Gillespie said approvingly as the drill commenced once more.
Truly, even the simplest of tasks is executed with an emphasis on effort. As the "A" backs ran in motion, they did not do so in a gentle trot. They were in a full sprint, drawing audible grunts of exertion from Trey Johnson and Garrison, among others.
That carried over into ball security drills, an area that the previous coaching staff made a fixture of practice. But these were not pedestrian attempts to strip the ball, as was sometimes the case during practices of years gone by.
Indeed, Gillespie -- working as freshman Andrew Buie's partner during one rep of the drill -- actually yanked so hard that he pulled Buie to the ground. Other players were routinely at least spun around by the person attempting to strip the ball.
The most minute of technical issues were addressed and corrected as often as possible.
During one drill in which players feigned losing their balance to practice using their off hand to brace themselves against the ground and keep running, Gillespie instructed players to be mindful of making sure their front leg was the opposite of the arm in which they had the ball tucked away. The reason? As the front knee bends and a player's body moves towards the ground, the potential exists for the ball to hit the knee and pop free.
"Fumbles occur when?" Gillespie asked his players after sharing that bit of advice.
"When you're in bad position," they responded in unison, showing just how much of a point of emphasis that has been.
The detail work continued, as "B" backs went through a drill where they took only their first step after a snap. They froze in that position, allowing Gillespie to criticize the angles of their feet and hips.
The goal is preventing players from taking too shallow of an angle or from running "too shallow" out of their break, which takes them out of an athletic position for blocking or running. The first step should be perfect, Gillespie explained, to allow the greatest possible explosion of power on the subsequent steps.
Urban was the only Mountaineer player limited. No red jerseys (used to signify a player is to be held out of action entirely) were seen on the grass practice field.
Eggleston will take a job leading fundraising efforts at a hospital in his hometown of Rochester, N.Y.
In a prepared statement, athletic director Oliver Luck said Eggleston "brought the department to new heights in terms of our athletic fundraising. He will be greatly missed, but at the same time I want to wish him nothing but the best."
BlueGoldNews.com's Tony Dobies spoke to Eggleston as the open period of practice ended, and a story with his comments is forthcoming.
Since players were still in "shells" on Tuesday (helmets, shorts and light shoulder pads), no players were actually tackled. But one could see the work that has been (and continues to be) done in terms of blocking assignments and coverage lanes.
A host of players rotated in and out of the spots as kick returners, as coaches apparently are still considering several options there. Among those who took reps were Tavon Austin, Devon Brown, Andrew Buie, Brodrick Jenkins and J.D. Woods.