Editor's Note: This is Part 1 of a five-part series focusing an advanced analytics look at the Texas Longhorns.

Replacing D’Onta Foreman will be no easy task.

Texas loses last year’s Doak Walker Award winner, who ran for more than 2,000 yards in only 11 games, never for fewer than 120 in any contest this past season and for more than 200 in three of his last five games in a Longhorns uniform. Foreman is now headed to the NFL, the third-round pick of the Houston Texans. He leaves behind a talented, albeit inexperienced group of running backs, but Texas is in a great position to make sure its run game doesn’t slow down in 2017.

Foreman accounted for the majority of the Longhorns’ carries (54.1%) and rushing touchdowns (55.6%) last year, along with more than 70% of their rushing yards (70.6%). His 50.35 rush EPA (Expected Points Added) was the third-most in the country and his 0.16 EPA/carry was the second-best among those with at least 200 carries last year.

But Texas brings back four starters on the offensive line, including an All-American, and a potential replacement in Chris Warren who has flourished as a starter, although in a small sample size. Warren has rushed for 836 yards and seven touchdowns in his first two seasons with the Longhorns, averaging an impressive 6.3 yards per carry. He put up 19.89 rush EPA over the last two years, including 11.06 in 2016, averaging 0.18 EPA/carry.

That’s even more efficient than Foreman (0.16), but the questions facing Warren going into 2017 will be: 1) Can he come close to maintaining that level of efficiency as a workhorse tailback over the course of an entire season the way Foreman did last year? and 2) Can he stay healthy for that entire season? Warren missed three games as a freshman with an ankle injury, the final eight games of last year with a knee injury and missed this year’s spring game with a hamstring injury.

If he can, the numbers suggest Warren is capable of maintaining his efficiency in a workhorse back role. He might not get the 323 carries Foreman did last season, but the numbers he put up in his only four career starts are encouraging. Warren averaged 149 rushing yards in those games, scoring seven touchdowns and averaging 6.5 yards per carry. That includes a school single-game freshman record 276-yard outburst against Texas Tech in 2015, his first career start. It was against the nation’s second-worst rush defense, but it was a sign of things to come.

In those four starts, he averaged 4.62 rush EPA per game, right around the 4.58 mark Foreman had last year, and 0.20 rush EPA per carry. The other five scholarship running backs on the roster have combined for 253 rushing yards, 4.4 yards per carry and a discouraging -15.67 rush EPA (-0.27 rush EPA/carry) in the last two years. Two have yet to get a carry, although one, Toneil Carter, ran for 60 yards on 10 carries in the spring game last month as the only healthy scholarship running back on the roster at the time.

The Longhorns bring back all but one starter from last year’s offensive line, a group that includes first-team All-American left tackle Connor Williams. He and the rest of the returners have combined to make 76 career returning starts. Looking at the rush EPA numbers teams have put up since 2009, those with at least 75 career starts returning on the offensive line saw their season-long rush EPA total jump by 6.52. Within that group, teams who had at least 15 rush EPA the previous year and had less than -25 rush EPA coming back like Texas does, their season-long rush EPA total increased by 5.25.

The Longhorns ran for 239.2 yards per game last year, good for No. 17 in the country. Foreman’s historic season was a silver lining of sorts during what ended up being their third straight losing season. Without him, they only have one running back with significant experience, although he has been productive in that time, but they do have four solid starters on their offensive line returning. Despite losing one of the program’s best rushers ever, high praise considering the history, Texas’ run game shouldn’t take much of a step back, if it even takes one at all.