Nobody could have scripted a much better turnaround season for Colorado than what unfolded in 2016. The Buffaloes rose from the Pac-12 cellar to claim their first divisional title and also reached a bowl game for the first time in a decade.

Can Colorado build on that success entering 2017?

There are significant holes for the Buffaloes to fill if they want to successfully defend their divisional crown. Colorado must replace eight defensive starters from a unit that ranked in the top 20 nationally in total defense (342.5 yards per game), passing defense (193.6 ypg) and scoring defense (21.7 points per game). The Buffaloes also must replace a four-year starter, Sefo Liufau, at quarterback. Liufau set or tied 98 school records on offense and finished his career as the school’s all-time leader both in total offense (10,509) and passing yards (9,568).

5 Storylines to Watch in Colorado’s Spring Practice

1. Can the Buffaloes rebuild their defensive line?

Colorado faces the unenviable task of replacing all three starters on the line from last season. Jordan Carrell, Josh Tupou and Samson Kafovalu combined for 144 tackles, 14.5 tackles for a loss and 9.0 sacks a year ago. They helped the Buffaloes rank in the top 20 nationally in both scoring defense (21.7 points per game) and total defense (342.5 yards per game).

Seniors Leo Jackson III and Timothy Coleman and junior Jase Franke figure to have bigger roles this season. Jackson III has made 14 career starts with the Buffaloes so far. He totaled 15 tackles a year ago. Coleman and Franke each had eight tackles and Coleman added 1.5 sacks.

Their ascension is not assured. Junior college transfers Javier Edwards and Chris Mulumba could challenge for starting jobs from day one. Edwards totaled two sacks and 51 tackles in two seasons at Blinn (Texas) College while Mulumba had 63 tackles, nine tackles for a loss and four sacks at Diablo Valley (Calif.) College in 2015.

2. Who will step up in the secondary?

Replacing impact players possessing NFL-level talent like Tedric Thompson, Chidobe Awuzie and Ahkello Witherspoon is never easy. Thompson led the team with seven interceptions in 2016 and the trio combined for 151 tackles and 49 pass break ups. Still, the quiver of arrows is far from empty for the Buffaloes in the defensive backfield.

Afolabi Laguda returns at safety where he was the top tackler (69 tackles) in the secondary last season. Ryan Moeller is a versatile defensive back who can be plugged in wherever he's needed. Isaiah Oliver and Nick Fisher could both be poised for breakout seasons after showing high disruptive playmaking potential in limited starts last season. Dante Wigley and Kevin George, a pair of highly regarded junior college transfers, should immediately push for playing time.

3. How will the offense look without Sefo Liufau?

Colorado got a sneak peek at life after Liufau last season after he missed three games with an injury. Steven Montez filled in as the starter and kept the offensive engine humming in Liufau’s absence. Montez threw for 823 yards, seven touchdowns and three interceptions during those three games and led Colorado to victories over Oregon and Oregon State.

Montez is the early favorite to become the new starting quarterback this season. He can throw the deep ball and has enough speed and mobility to extend plays. Montez isn’t a true dual-threat quarterback in the mold of Liufau. The sophomore is a closer fit to the prototypical pocket-passer mold. Colorado’s offense will feature much more vertical passing with Montez at the helm.

Montez will see some competition for the top spot. Freshman Sam Noyer redshirted last fall and showed high upside in practices. True freshman Tyler Lytle is a pro-style quarterback with a strong arm and good football IQ.

4. Will the kicking game see improvement this year?

Field goal kicking proved to be a major weakness for Colorado throughout last season. The Buffaloes connected on just 17 of 26 (65.4 percent) field goal attempts. Punting wasn't much better with Colorado averaging 40.1 yards per punt while kicking 5.3 punts per game. The Buffaloes ranked 81st nationally in punting and 104th nationally in field goal kicking.

Davis Price and Chris Graham will likely compete for placekicking duties again this season. Price has a stronger leg and, if he improves his accuracy, could unseat Graham as the primary field goal kicker. Alex Kinney showed some progress as a punter a year ago, increasing his per punt average from 40.1 to 41.3 yards. Kinney will need to make even bigger strides in 2017 to turn the punting game into a major defensive weapon.

5. What will the defense look like under a mostly new staff?

Successful programs often face turnover on their staffs from one season to the next as assistant coaches leave for promotions elsewhere. Colorado felt those winds of change blow through the program and reshape how the defensive coaching staff will look in 2017.

Defensive coordinator Jim Leavitt left after two seasons to take the same position at Oregon. Safeties coach Joe Trumpkin resigned in January amid allegations of domestic violence against his ex-girlfriend. Defensive line coach Jim Jeffcoat remains the lone holdover from a season ago under new defensive coordinator D.J. Eliot.

Eliot is well versed in using the 3-4 defensive alignment that's favored by head coach Mike MacIntyre. The schemes should remain relatively unchanged from a season ago, although execution could vary depending on how well new starters can step up and fill larger roles.

Colorado’s Pre-Spring Outlook in the Pac-12

If the Buffaloes can successfully reload on defense, there’s no reason to believe Colorado can’t seriously challenge for back-to-back Pac-12 South crowns. There’s enough talent returning at the offensive skill positions to make the Buffaloes dangerous on that side of the ball again. Colorado has enough horses to compete with the best teams in the league. The fact that the Buffaloes have risen so high in just a year’s time, speaks to the solid winning foundation that Mike MacIntyre has finally built in Boulder.

— Written by John Coon, who is part of the Athlon Contributor Network. Coon has more than a decade of experience covering sports for different publications and outlets, including The Associated Press, Salt Lake Tribune, ESPN, Deseret News, MaxPreps, Yahoo! Sports and many others. Follow him on Twitter @johncoonsports.