Edwards and Dixon are slated to return in 2019. Collins is slated to be a restricted free agent, and it remains to be seen what kind of tender the Ravens will offer. Javorius Allen, who took a backseat on offense last season, is scheduled to become an unrestricted free agent.

"All those guys have very positive traits," Roman said. "One is never enough in this league. You've got to have a stable of them.

"Running backs are all unique, very much like quarterbacks. They all have a different style. We don't necessarily have to have three clones of the same guy."

Ideally, every team would love to have one running back that stands out from the rest. The Ravens had that with Jamal Lewis when they won Super Bowl XXXV and with Ray Rice when they took home Super Bowl XLVII.

Both of those players were major difference-makers who made the offense go. Baltimore hasn't had a running back like Rice – a three-time Pro Bowler – since they drafted him in the second round in 2008 and released him in 2014.

Like Roman said, it's a player that can make big running plays happen on their own.

"We'll get all this done for you, and if you deal with that one guy – however you deal with him – that's how you get those big plays," Roman said.