Perhaps it's because every Southeastern Conference backfield needs a JaTarvious and a Cartavious.
Or maybe every running game needs a "Boobie" and a "Tank."
Auburn didn't appear to have an immediate need at running back with an existing stable that includes redshirt sophomore JaTarvious "Boobie" Whitlow, sophomore Shaun Shivers, redshirt freshman Harold Joiner and true freshman D.J. Williams. That, however, didn't stop Gus Malzahn's Tigers from adding Cartavious "Tank" Bigsby of LaGrange, Georgia, during Wednesday's start to college football's early signing period.
"You can't have enough depth at the running back position in our league," Malzahn said Wednesday in a news conference, "and you've seen that throughout the years."
The SEC's dominant showing in the early signing period was reflected at running back, with five of the top eight nationally who signed at that position choosing to compete in the same league. Geography was not an issue, as Kendall Milton of California picked Georgia, MarShawn Lloyd of Maryland selected South Carolina and Jase McClellan of Texas picked Alabama.
Roydell Williams, who is from the Birmingham suburb of Hueytown, was the lone elite SEC running back signee who stayed within his state, doing so by inking with the Crimson Tide.
Georgia should have one of the league's youngest backfields next season, with Milton joining sophomore James Cook, redshirt freshman Zamir White and true freshman Kenny McIntosh. Junior D'Andre Swift, a 1,000-yard rusher for two consecutive seasons, is expected to bypass his final year for an opportunity in the NFL.
"Kendall, I think, was attracted to the fact that he knew he had the potential of two guys leaving with (Brian) Herrien being a graduate and being a senior, and with the likelihood of Swift possibly coming out," Bulldogs coach Kirby Smart said Wednesday. "He's sitting there going, 'You know what? There's an opportunity there.' When you look at it as a running back and say they could be losing two guys - it's very similar to years past when we had Sony (Michel) and Nick (Chubb). You're always exploring those options.
"We certainly felt that Kendall comes from a really strong family, and they came and visited all the schools across the Southeast and really liked what Georgia had to offer. I am super pleased to get him. He was one of our leaders in the class, and I'm excited about what he's going to bring to the table."
Alabama will offer the potential for early playing time should current junior Najee Harris decide the Citrus Bowl against Michigan will be his final college game. Brian Robinson would be a senior next season and the most experienced running back in a pack that includes Keilan Robinson, Jerome Ford and Trey Sanders, a five-star signee in the 2019 cycle who sustained a season-ending foot injury during August workouts.
Injuries and early departures at running back have impacted Malzahn's tenure at Auburn, with injuries to Kamryn Pettway in 2016 and both Pettway and Kerryon Johnson in 2017 resulting in top-10 rankings giving way to season-ending losing streaks both years. Pettway and Johnson left early after the 2017 season.
Keeping his running backs active and happy may be among Malzahn's biggest challenges in 2020.
Whitlow has rushed for 1,526 yards and 5.1 yards per carry through his first two seasons. Shivers earned his place in Auburn lore with the winning touchdown run in last month's Iron Bowl that sent Alabama safety Xavier McKinney's helmet flying, while Williams showed plenty of promise with his 13-carry, 130-yard performance in October's 23-20 loss at LSU.
Now Bigsby, a national top-five running back, joins the mix.
"He's a one-play-drive type of guy," Malzahn said. "From anywhere on the field, he can take it to the house. He has great balance and great instincts, and he can break tackles. You have to break tackles in this league if you're going to be successful.
"A lot of our running backs are pretty versatile, and there could be times you see two on the field at the same time moving forward. We really have some really talented guys in that room."