Midfielders Benny Feilhaber and Roger Espinoza have a litany of responsibilities every time Sporting Kansas City takes the field. From possession and chance creation to tracking back and disrupting opponents' attacks, both players exert most of their energy from box to box as vital cogs in Peter Vermes' 4-3-3 system.

Hence the term "box-to-box" midfielder, a moniker given to those who contribute valuably on both sides of the ball. Major League Soccer's Audi Player Index ranked the top 10 box-to-box midfielders on Tuesday, and Feilhaber and Espinoza checked in at No. 3 and No. 7, respectively.

The scores below are the average of each player's Audi Index score per game:

RANK SCORE PLAYER CLUB 1 530 Steven Gerrard LA 2 512 Frank Lampard NYC 3 460 Benny Feilhaber SKC 4 396 Mohammed Saeid CLB 5 380 Andrea Pirlo NYC 6 332 Tony Tchani CLB 7 328 Roger Espinoza SKC 8 317 Cristian Roldan SEA 9 317 Will Johnson TOR 10 280 Ricardo Clark HOU

So why do Feilhaber and Espinoza rank so high on the list? The Audi Player Index uses 86 different metrics to compute a score for each midfielder, placing extra value on assists, created chances, passing accuracy, dribbles and duels won. Let's take a look at the Sporting Kansas City duo's well-balanced statistical profiles.

Benny Feilhaber

The 31-year-old has followed up his MVP-caliber 2015 season with another fantastic campaign.

Feilhaber has six goals to go with 12 assists, tied for third most in MLS. He is one of five players with at least six goals and 10 assists in 2016.

He is the only MLS midfielder with at least 50 chances created and 150 duels won.

Among the top 15 midfielders in chance creation, Feilhaber has the highest duel success rate at 57.3 percent.

Roger Espinoza

The tireless Honduran has started all 28 MLS appearances in 2016, putting together arguably his best season in a Sporting Kansas City uniform.

Espinoza has an MLS career-high five assists.

He ranks among the top 10 MLS midfielders in each of the following: duels won (2nd), tackles won (10th), recoveries (10th), touches (10th) and successful passes in the attacking third (5th).

He is the only MLS midfielder with at least 400 successful passes in the attacking third, 150 duels won and 50 tackles won.

Sporting Kansas City owes much of its success in 2016 to Feilhaber and Espinoza, who are likely to feature in the club's next match at Real Salt Lake on Oct. 16. Peter Vermes' men currently hold the sixth and final playoff spot in the Western Conference, two points behind fourth-place Real Salt Lake. A victory could see Sporting KC vault into position to host a home playoff game, while a loss could mean the end of its five-year postseason appearance streak.