Over the last two seasons, Michigan State has been one of the more balanced teams in the Big 10 and throughout the country. The Spartans’ success can largely be attributed to a dominant defensive unit, an explosive running game and an efficient passing attack that doesn’t turn the ball over. As the 2015 college football season approaches, the Spartans’ biggest weakness is the lack of depth at running back — even as the defense and passing game are exceedingly strong.

Last year, the potency of the Michigan State running back corps played an important role in carrying the team to an 11-win season and a victory over Baylor in the Cotton Bowl. They were led by Jeremy Langford‘s 1,360 rushing yards and 19 touchdown runs in combination with Nick Hill‘s 596 rushing yards and nine touchdowns.

The Spartans’ production in the running game allowed quarterback Connor Cook to have a stunningly efficient season under center in 2014.

Now, with Langford and Hill no longer lining up in the backfield, Michigan State desperately needs a tailback on the depth chart to step up, along with a competent backup running back.

With presumed 2015 starter Delton Williams facing a potential multiple game suspension this season due to legal issues stemming from his arrest in March for brandishing a firearm in public during a traffic dispute, Michigan State’s depth of the running back position has been weakened. At this point, Williams is expected to be reinstated by the program, though without a scholarship and with the possibility of suspension.

Williams’ off-the-field issues could deal the Spartans a huge blow at the position in the event he is suspended for any length of time. The situation should be especially concerning to the program considering his solid production in limited playing time last season. Williams rushed for 316 yards and five touchdowns, along with a per carry average of 5.9 yards. Given his strong production as the third running back in 2014, Williams was — and may still be — expected to continue Michigan State’s success at tailback.

Other than Williams, the only other running back on the depth chart with any real game experience is Gerald Holmes. Last season, Holmes was only given 15 rushing attempts in which he rushed for a mere 44 yards. With the prospect of Williams missing multiple games this season, Holmes promises to receive a large share of the carries in the Spartan offense.

The remainder of the running backs on the depth chart consist of a totally inexperienced group of players. These tailbacks include redshirt freshman Madre London and true freshman L.J. Scott. London is a likely candidate to receive the majority of the reps as a backup to either Williams or Holmes. Scott, though, may be the most intriguing option on the depth chart.

Scott is a four-star recruit out of Hubbard, Ohio who chose Michigan State over rival Ohio State back in February. He is ranked No.7 among running backs in the 2015 recruiting class. Though Scott may currently be listed as fourth in the depth chart, he has the talent and athletic ability to receive a solid amount of game experience this season. While Scott is clearly the running back of the future in East Lansing, he likely won’t receive most of the carries early on.

Michigan State’s inexperience and lack of depth at running back is identifiably their biggest weakness in the upcoming season. Though this weakness may ultimately be cured by the emergence of Scott, it may still cost the Spartans against the likes of Oregon and Ohio State.

Dan is a Big 10 Football Beat Writer for www.RantSports.com. You can follow him on Twitter @danescalona77.