Starters in, starters out. That’s college football. Players’ eligibility expires, and they leave for the rest of their lives, whether that includes the NFL or not.

And they leave behind shoes of various sizes that need to be filled.

Our concern with this series? The biggest shoes -- in some cases Shaq-like size 23s.

Biggest shoes: TEs Zach Ertz and Levine Toilolo

These guys rate a tandem because Ertz was a unanimous All-American, Toilolo was a towering No. 2 and they represented one of the great innovations during Stanford's rise into the nation's elite: The "Big" formations featuring multiple tight ends who catch the ball like receivers and block like tackles. When you toss Coby Fleener in there from 2011, and you recall how special that troika was. And now all three are gone and no tight end remains on the roster who has caught a pass. This is further notable because both Ertz and Toilolo could have returned this fall. Ertz's decision to leave wasn't a surprise. He's a potential first-round NFL draft pick. Toilolo's was, and more than a few folks think he made a mistake, surrendering an opportunity to be the lead guy, and answer questions about his inconsistent hands. It also doesn't help that the Cardinal lost their Nos. 2 and 3 receivers, running back Stepfan Taylor and receiver Drew Terrell. But the void isn't just about catching the ball. Stanford's tight ends have played a key role in the rise of a dominant power running game. While the offensive line should be strong again this fall, it's questionable if the "Big" formations will be as fearsome, at least the tight end options.

Stepping in? Sophomore Luke Kaumatule

Kaumatule, a 6-foot-7 Hawaiian, certainly looks the part, and he is the early leader after a strong first spring session, though he's still learning the ins and outs of the position. Coach David Shaw also moved senior Eddie Plantaric and junior Charlie Hopkins, former defensive linemen, to the position, and senior Davis Dudchock brings veteran leadership and knowledge. Sophomore Alex Frkovic is trying to come back from a knee injury and sophomore Chris Harrell is promising but needs to get bigger and stronger. It's important to keep in mind that Stanford isn't looking for just one guy. It would like at least three to step up because it has plenty of designed plays with three on the field at the same time. Another thing to keep in mind: Stanford is deep at fullback, led by former tight end Ryan Hewitt, who at 6-foot-4, might be the tallest fullback in the nation. There's no reason that when Shaw says, "Give me a big, nasty guy who can run and catch," he won't finger a fullback for the role.