INDIANAPOLIS - The NFL's two leading rushers last season were rookies, and that running back draft class pales when compared with what NFL evaluators are scouting at the combine this week. It was an example of how the position can produce early contributors and offered a prelude to what could come from rookie running backs in 2017.

"When you look at the running back position, we think it's a possible historic class about how many guys and where they would have gone in previous drafts," said Howie Roseman, the Eagles' executive vice president of football operations.

The Eagles are going to need a running back this offseason. Ryan Mathews, who is recovering from a neck injury, could be a salary-cap casualty when he's healthy. The Eagles are expected to return Darren Sproles and Wendell Smallwood to the backfield, but they're likely going to add to that group. Because of the strength of this draft class, it's a good bet the addition is a rookie.

The question, of course, is when. NFL Network draft analyst Mike Mayock said five running backs will have first-round grades and predicted three will go in the first round. The top three running backs are LSU's Leonard Fournette, Florida State's Dalvin Cook, and Stanford's Christian McCaffery. But after those three is a collection of other running backs who could emerge as lead rushers. Teams have a choice to make: Do they take a potential elite running back in the first round, or does the deep class allow them to wait until a later round to address the position?

"With the running backs we've got in our class and next year's running backs, a lot is going to change," Fournette said. "With this group a lot of these players are going to succeed in the NFL and contribute as soon as they get there."

Dallas' Ezekiel Elliott was the No. 4 overall pick last April and led the NFL in rushing while helping the Cowboys to first place in the NFC East. He is evidence that it can be prudent to make an early investment in an elite running back. But the No. 2 rusher last year was Chicago's Jordan Howard, a fifth-round pick who was evidence that quality running backs can be found even on the draft's third day. Eagles executive Joe Douglas, who is setting the draft board, was the Bears' college scouting director last season and was influential in the Howard pick.

"If you get a great running back, it changes the game," Douglas said. "You saw that with Dallas this year. But I think you can get not only running backs, great players at every level of the draft."

The Eagles likely won't have a choice with Fournette. The 6-foot-1, 240-pound bruiser averaged 6.2 yards per carry and has a punishing style that can make him a top back in the NFL. There is anticipation to see how fast he can run at his size, and he predicted that he would run the 40-yard dash Friday in 4.4 seconds.

Mayock has Cook rated as his top running back. At 5-11 and 213 pounds, Cook was a first-team all-American last season after rushing for 1,765 yards and topping 1,000 yards in three consecutive years for the Seminoles. Teams will need to examine his medical and off-field history, but he also fits the profile of a potential franchise running back.

McCaffrey, who is 6-0 and 197 pounds, is an ideal fit for teams looking to exploit mismatches. He can be used so many ways, ranging from running to receiving to even specialist roles. The son of former NFL receiver Ed McCaffrey set an NCAA record with 3,864 all-purpose yards in 2015 and led his team in rushing and receiving yards, winning the Paul Hornung Award for the nation's most versatile player.

"I definitely believe I can be an every-down back and a specialist. Do them both at the same time," McCaffrey said. "Something I really pride myself on is not just being a running back that can catch the ball. But if I move out to the slot, I become a receiver. If I move out to X or Z, I become a receiver and not just a running back. I really try to pride myself on route running, catching, and being able to be a mismatch anywhere on the field."

After the top three, there is still potential Pro Bowl talent. But also more risk. Oklahoma's Joe Mixon might be in the top category if teams did not have character concerns. Mixon was not invited after being charged in punching a woman. The incident was caught on tape. Now, teams will travel to Norman, Okla., for more research.

Tennessee's Alvin Kamara has tantalizing ability, but he had only 210 carries in college. So there is limited evidence that he can be a top running back even though his rushing and receiving ability, along with a 5-10 and 215-pound frame, fits the prototype. The Eagles met with Kamara in Indianapolis.

"I talked about that a little bit with teams, and it's honestly a good thing, the limited amount of carries," Kamara said. "Of course they wanted to see more production, but the limited amount of carries - save it for the league."

The list of intriguing rushers is lengthy after that quintet. Texas' D'Onta Foreman, who is 6-foot-1 and 249 pounds, rushed for 2,028 yards last season and was named the nation's top running back.

Pittsburgh's James Connor is 6-2 and 235 pounds and was the ACC's player of the year as a sophomore in 2014 after rushing for 1,765 yards and 26 touchdowns. He overcame Hodgkin's lymphoma in 2015 and was first-team all-conference last season.

Wisconsin's Corey Clement was a big recruit out of Glassboro High School who topped 100 rushing yards in eight of 13 games last season. He's one of the top local players in the draft. But at his position, he's surrounded with top talent who could have teams finding top-of-the-rotation rushers throughout the draft.

"We've got the top guys in this class at running back," Cook said. "It's probably one of the best . . . seen yet."