College football follows a specific life cycle. A new cycle begins in just a few days from the publication of this article with 2017 National Signing Day. The new wave of incoming talent onto the landscape replaces those athletes exiting.
Replacing players so frequently contributes to the excitement and unpredictability of the sport. It also makes the task coaching staff face particularly challenging.
Coaches around the Pac-12 face an offseason with some uncertainty at key positions, the result of losing premier playmakers. The voids left by the following 12 Pac-12 standouts (in alphabetical order) will be responsible for the most hours logged among coaching staffs around the conference this offseason.
Budda Baker, S, Washington
Defense paved Washington's road to its first conference championship since 2000. The engine for the Huskies' No. 8-ranked scoring defense was their do-everything safety. Baker registered a team-high 71 tackles on the season, providing support against both the run and pass.
He blitzes as effectively as he disrupts passes -- and he disrupts passes quite expertly.
Jimmie Gilbert, DE, Colorado
Colorado owes much of its surprisingly resurgent season to the performance of a stellar defense. Despite a couple of lopsided losses to close an otherwise great campaign, the Buff defense still managed to finish ranked No. 20 nationally in points allowed.
Credit the tenacity of pass-rushing expert Gilbert for much of the Buffs' success. Gilbert made 10 sacks with 14 tackles for a loss on the year, setting the tone for a defense that ranked 20th against the pass.
Zane Gonzalez, K, Arizona State
The descriptor "best" gets thrown around too loosely in today's sports media climate, but Gonzalez has the statistical credentials to back up any such declarations. Gonzalez leaves Arizona State as the NCAA's all-time most prolific kicker with 96 made field goals.
Having Gonzalez on the roster virtually guaranteed the Sun Devils at least three points any time they crossed opponents' 40-yard line.
Adoree' Jackson, CB/Ret., USC
College football has seen few quite like Jackson. That's not just recently, either. Jackson's multifaceted skill set make him a historical outlier in a vein similar to 1997 Heisman Trophy winner Charles Woodson.
Jackson won the Jim Thorpe Award as college football's top cornerback in 2016, but his unique playmaking abilities as both a wide receiver and returner added a dynamic to USC that head coach Clay Helton will not be able to duplicate employing just one player. The job of replacing Jackson is a multiple-person endeavor.
Sefo Liufau, QB, Colorado
No Buff was more synonymous with Colorado football's return to prominence than Liufau. He signed onto head coach Mike MacIntyre's first recruiting class, took over as the starting quarterback midway through the 2013 campaign, and only relinquished the job due to injury.
And, as Colorado's 10-win campaign proved, losing Liufau was indeed a difficult proposition. He was sidelined for stretches, if not all of the Buffs' four losses. Perhaps the game experience backup Steven Montez gained will have him prepared to fill Liufau's shoes.
Gabe Marks, WR, Washington State
Wide receivers with lofty numbers come standard in Mike Leach's air-raid offense. But career statistics that put Marks among the best pass catchers in conference history do not explain the full extent of his place with the Cougars.
Marks combined speed and elusiveness that often turned short and mid-range throws into long gains. He could also blow past coverage for game-breaking gainers.
Christian McCaffrey, RB, Stanford
McCaffrey dazzled for each of the last two seasons, shouldering every responsible put upon him in Stanford's offense. The 2015 Heisman Trophy runner-up functioned as a dependable, every-down back, but also served as one of the Cardinal's most reliable pass-catching options.
Add his explosiveness in special teams, and replacing McCaffrey is a multifaceted endeavor for Cardinal head coach David Shaw.
Takkarist McKinley, DE, UCLA
McKinley arrived on UCLA's campus midway through the 2014 season, a JUCO transfer with plenty of unrefined promise. He evolved into the heir apparent for Bruin standouts like Owa Odighizuwa and Cassius Marsh. McKinley even outshined former 5-star recruit Eddie Vanderdoes as the breakthrough star on UCLA's defense this past season, racking up 10 sacks.
Even when McKinley wasn't racking up sacks, he made life difficult on opposing quarterbacks, establishing residency in opponents' backfields.
UCLA head coach Jim Mora must replace both McKinley and Vanderdoes. Neither will be easy, but McKinley's uncanny motor should prove more difficult to replicate.
John Ross, WR, Washington
Few players can match the speed Ross brought to both the offense and special teams at Washington. Ross' big-play ability manifested in an eye-popping 17 touchdown receptions in 2016, complementing a season-long total of 1,150 yards.
He also averaged nearly a quarter-field per kickoff return, and ran one kickoff back for a touchdown. That's a difficult dynamic for Chris Petersen to replicate as the Huskies seek to repeat as Pac-12 champions.
JuJu Smith-Schuster, WR, USC
USC has a long-standing tradition of game-changing wide receivers. A 5-star recruit coming out of local powerhouse Long Beach Poly, there was never any doubt Smith-Schuster had the potential to become the latest in the Trojans' impressive lineage.
He leaves USC with more than 3,000 career yards and 25 touchdowns, but numbers only tell part of the story. His reliability as a possession receiver keyed the USC offense, and the threat he poised whenever he lined up opened the field for Trojan teammates to get loose.
USC remains well-stocked with talented receivers, like Rose Bowl Game hero Deontay Burnett. But someone must emerge as the go-to guy Smith-Schuster functioned as for the last two seasons.
Solomon Thomas, DE, Stanford
Stanford's #PartyInTheBackfield lived on through 2016, thanks to Solomon Thomas. The standout defensive end anchored the Cardinal defense in 2015, and had a 2016 Rose Bowl Game worthy of national attention -- were it not for teammate Christian McCaffrey putting on one of the most spectacular, individual efforts ever seen in the Granddaddy of 'Em All.
This year's bowl game, the stage belonged to Thomas. He ended his collegiate career with two tackles for a loss, a sack and seven tackles in the Sun Bowl. That performance provided a fitting cap to a stellar career.
Tedric Thompson, CB, Colorado
In 2014, the Colorado defense combined for three interceptions all season long. Thompson was responsible for each and every one. Fast-forward two years, and Thompson more than doubled his production with seven picks. The final two came, fittingly, in Colorado's Pac-12 South-sealing win over Utah.
The entire Buff secondary was outstanding in 2016, and Colorado's also faced with replacing standout Chidobe Awuzie. However, it's Thompson's ball-hawking that will prove most difficult to replace for the Buffaloes' new defensive coordinator.