Pac-12 quarterbacks generated much hype entering last season, and the league’s receivers benefited from veteran presences under center throughout the year. USC’s Nelson Agholor and Arizona State's Jaelen Strong provided true top-line sizzle, while Washington State’s Vince Mayle set an eyebrow-raising statistical pace (106 catches, 1,483 yards).

Those three receivers, though, were part of an exodus of Pac-12 passing game talent following 2014. Many of the league’s marquee quarterbacks also have left, so 2015 is shaping up to be the year of the running back — especially because many of the Pac-12’s defensive fronts seem to be in rebuilding mode.

This question, then, is up for debate: Who assumes the role of alpha dog among Pac-12 receivers now that talents such as Agholor and Strong are gone? Here’s our stab at it:

Lombardi: It’s impossible to ignore the explosive young talent that Oregon and USC have amassed on the perimeter, and it seems inevitable that both of those offenses will again churn out impressive production through the air. Washington State’s Dom Williams also has turned heads this spring, and he looks like a lock to be among the Pac-12’s statistical leaders (he is in a Mike Leach offense, after all). I’m also intrigued by D.J. Foster’s new role in the Arizona State attack — coordinator Mike Norvell told me that Foster will literally line up at every single skill position — so his versatility and receiving production might make a case for alpha-dog consideration by the time we get rolling.

Nelson Spruce caught 106 passes at Colorado last season. AP Photo/David Zalubowski

As of now, though, my proven man is Colorado’s Nelson Spruce. The Buffs’ struggles as a team have largely pushed him under the radar, but Spruce turned into a statistical machine in 2014 following the departure of teammate Paul Richardson to the NFL. His 106 catches tied Mayle for the conference lead, and his 12 touchdown receptions also set the league pace. Those are impressive numbers for a player who was the focus of opposing teams’ top defensive backs throughout the season.

Spruce has been looking to increase his explosiveness this offseason — “I’m working to be quicker in and out of breaks,” he has said — so it’s a good bet that he’ll improve on that 11.3-yards-per-catch average, especially as quarterback Sefo Liufau continues to mature. Spruce should be loose in his senior season, and if Colorado can muster some team improvement, his production won’t fly so far under the radar anymore. That’s why I think he’s the Pac-12’s top dog entering the year. That, of course, could change if one of league’s promising youngsters takes 2015 by storm.

Jennings: When I sat down to look at which wide receiver I thought could become the alpha dog in the Pac-12 in 2015, I thought about what criteria had made other receivers that “top dog” in recent years. Many of those receivers had several (if not all of) the following four things:

A returning QB A real rushing threat to keep defenses honest Another WR threat to make sure the defense didn’t just key on said player A team that won enough games to give them legitimacy

Cayleb Jones should have plenty of chances to make big catches for Arizona. Jonathan Ferrey/Getty Images

So, let’s look at that when evaluating my choice -- Arizona wide receiver Cayleb Jones, the Wildcats’ top returning wide receiver from 2014.

1. Anu Solomon is one the league’s best returning quarterbacks and we’ve all seen the jumps other quarterbacks have made in the Pac-12 between their first and second seasons starting (e.g. Jared Goff’s completion rate went up and his touchdown-interception ratio nearly tripled; Cody Kessler’s completion rate went up and his touchdown-interception ratio nearly tripled). I’m not saying Solomon is going to make Goff-like or Kessler-like strides, but improvement will happen and Jones will be a beneficiary.

2. Nick Wilson is a serious rushing threat who probably doesn’t get nearly enough credit. The Wildcats lost three starters on their offensive line, but I don’t think that will slow Wilson too much. He’ll still be a guy who draws plenty of attention off Jones as teams try to slow him.

3. Samajie Grant, the team’s second-leading receiver a season ago, also returns. Teams can’t look at Jones as the only threat. Again, anything that keeps a defense honest is a good thing.

4. You can be a fantastic wide receiver and put up huge numbers, but unless your team wins enough games, nobody really thinks it’s legitimate. When’s the last time a player from a losing team won a major award in college football? Arizona is the defending Pac-12 South champion. The Wildcats should be in the thick of it again this season. It's an older and more mature team that's hungry after losing to Boise State to close its 2014 season. Arizona will be dangerous again.

Jones has the cards falling his way in each of those categories. Spruce can’t say the same; neither can some of the conference’s other top returning receivers such as River Cracraft, Victor Bolden and Jordan Payton. All of those players are great receivers, but I just feel like this is Jones’ spot to lose, based on so many things going his way.