Despite reaching the Pac-12 Conference Championship Game for the fourth time since 2012, the ‘17 season ended on a sour note for Stanford football. The Cardinal dropped heartbreakers to USC in the league title game, and coughed up a lead in the Alamo Bowl against TCU.

Those final few weeks can be described as bittersweet, however. The losses may have put a damper on what was an unexpected run to the top of the Pac-12 North, but perhaps as unexpected came running back Bryce Love's announcement he is returning to Stanford for the 2018 campaign. Love put up monster numbers en route to becoming the Cardinal's fourth Heisman Trophy runner-up since 2009.

Love's return fuels an impressive offensive lineup for Stanford in 2018, but the defending Pac-12 North champs are not without question marks heading into spring practices. The Cardinal have contributors to replace — both on the field and the sidelines — and glaring question marks in what has been the program's bread-and-butter under head coach David Shaw, its defense.

5 Storylines to Watch During Stanford's Spring Practice

1. Tavita Pritchard's offense

Mike Bloomgren's departure from Stanford to take over as head coach at Rice leaves the Cardinal offense in the hands of Pritchard. Pritchard's 10-yard touchdown pass to Mark Bradford in 2007 completed what was then the largest upset in college football history, and kicked off the ongoing rivalry between the Cardinal and USC.

Now, Pritchard takes on a new role as overseer of the Cardinal offense. Things have changed dramatically since that October night in 2007, with a veritable assembly line of NFL talent and Heisman contenders rolling through Stanford. How Pritchard adjusts to his move to coordinator can shape the Cardinal's 2018.

2. Quarterback situation

Stanford rebounded from a sluggish start to 2017 with a strong second half. Of no coincidence, quarterback K.J. Costello settled into the starting role full-time down the stretch, and the Cardinal started to click.

An injury has Costello shelved for spring, however, and with Keller Chryst transferred out of the program, the forecast at quarterback is uncertain. Two of the most highly touted prospects in the 2018 signing class play the position, Tanner McKee and Jack West. Until they arrive, however, Stanford has two quarterbacks to run the show in spring — Jack Richardson and Davis Mills.

After Costello in 2017 and Chryst in '16 took over midway through the campaign, the importance of that second-string job is evident at Stanford. Spring practices begin the competition in earnest, and with first-string opportunities.

3. Rebuilding the secondary

The Cardinal cultivated a reputation on their defense throughout David Shaw's tenure as head coach, first with Derek Mason as coordinator, and now under Lance Anderson. Stanford maintained a high level on that side of the ball through various departures, but 2017 marked the first truly evident signs of attrition taking their toll.

Stanford ranked No. 80 nationally against the pass, the result of the front seven generating somewhat less pressure than in years past, but also due to inconsistencies in the secondary. The question marks the Stanford secondary faced amplify heading into spring practices, with standout performers Quenton Meeks and Justin Reid both leaving early for the NFL.

Veteran Alijah Holder returns to anchor the unit, but Stanford needs returners like Frank Buncom IV and Brandon Simmons to step up in the coming months.

4. A horrible hole up front

Defensive tackle Harrison Phillips — who goes by @horribleharry66 on Twitter — emerged as the latest standout from the Stanford defensive line. Surely opposing quarterbacks who describe Phillips bearing down on them as horrible are relieved, but the Cardinal need someone to take his place.

What's more, the loss of his seven sacks exacerbates the previously noted slight decline Stanford experienced in that category a season ago. The Cardinal lacked a dominant rusher off the edge as Stanford's typically had in years past, featuring stars like Trent Murphy and Solomon Thomas. To wit, the team's second-leading sacker in 2017, Bobby Okereke, plays inside linebacker.

In addition to filling the sizable hole Phillips leaves on the interior of the line, Stanford also needs a premier defensive end or outside linebacker to establish himself if the Cardinal are to match previous season's performances.

5. Running back rotation

Bryce Love garners the headlines, but Shaw's teams have long featured impressive depth at running back. That's no different in 2018, with Cameron Scarlett — who had eight rushing touchdowns as a goal-line back last season — returning behind Love.

A name to follow during the offseason, however, is Trevor Speights. The 5-foot-11, 205-pound Speights saw 36 carries in 2017. If he can show himself to be a reliable option, Shaw can attack opposing defenses with a fresh trio of ball carriers — or quartet, given Costello's ability to scramble.

— Written by Kyle Kensing, who is part of the Athlon Contributor Network and a sportswriter in Southern California. Kensing is publisher of TheOpenMan.com. Follow him on Twitter @kensing45.