All players are equal, but some players are more equal than others. That's the basis of our "most important players" series.

There are a few rules you need to know:

1. Quarterbacks are ineligible.

2. "Most important" doesn't equal "best." (Note: Sometimes the most important player is the best player.) I think we can all agree that a season ago, players such as Mike Bercovici and Jerry Neuheisel proved how very important they were to their respective teams.

3. Even if they were the most important, they're quarterbacks and therefore ineligible (see rule No. 1). Keep up, guys.

A healthy Aziz Shittu would go a long way toward curing Stanford's ills on the defensive line. AP Photo/Darron Cummings

Stanford: DL Aziz Shittu

2014 production: 13 tackles, 1.5 TFL, 1 sack, 1 pass breakup (played in only five games before suffering season-ending injury)

Why Shittu is important: Stanford does not list a single nose tackle on its roster. For a defense that has been so reliant on block-gobbling fire hydrants in the middle -- see Terrence Stephens and David Parry -- that's a frightening prospect.

Shittu is the one player who potentially can bring that interior veteran sturdiness to Stanford's defensive line. Though he's still listed as an end, the positional versatility Shittu began to showcase last offseason -- he shifted effectively between end and tackle -- gives the Cardinal hope on the inside.

Shittu delivered the best game of his career before succumbing to a season-ending non-contact injury in practice last season. His loss hurt immediately: With Parry also out, the Stanford line's backbone dissolved, and the end result wasn't pretty against explosive offenses such as Arizona State and Oregon.

All three 2014 starting defensive linemen -- including Parry -- are gone, so it's fair to be skeptical of a front that will be relying heavily on youngsters Harrison Phillips and Solomon Thomas. Though those two have packed on considerable muscle this offseason to complement the addition of graduate transfer Brennan Scarlett, Shittu's play ultimately represents the tipping point for Stanford's defensive line.

Spring practice was a no-go since he was still recovering from last season's injury. Assuming Shittu is firing at full capacity come September, the Cardinal will add a robust, adaptable presence to their line -- one who generate breathing room for the fresh faces surrounding him.

On the other hand, if Shittu doesn't deliver in a big way, Stanford will be skating on the thinnest of ice up front. Since a shaky defensive line could be the primary ingredient of defensive disaster, there's a lot of pressure on the senior.

By the way, we're about to see a Stanford player wear John Elway's No. 7 for the last season ever. That jersey will head into official retirement after Shittu is done with it following this critical campaign.