Adam Schefter says it's a major deal that big time college players are backing out of bowl games to prevent the risk of injury before the NFL draft. (0:51)

As late as Friday evening, all public indications suggested Christian McCaffrey would suit up for Stanford against North Carolina in the Hyundai Sun Bowl on Dec. 30.

McCaffrey, who announced his intentions to enter the 2017 NFL draft two weeks ago, said he looked forward to one last opportunity to play with his Cardinal teammates. He was sweating slightly Friday as he walked off the Stanford practice field, even on a particularly chilly afternoon.

"I'm really focused on UNC," McCaffrey said at the time. "I just wanted to make the announcement to get it out of the way. I'm just focused on UNC now."

But something changed in the 50 hours between then and McCaffrey's early Monday morning tweet, in which he officially declared the end of his college career.

McCaffrey's announcement came just three days after LSU star Leonard Fournette said he also would be forgoing a bowl game to focus his preparations for the NFL draft. It's unclear if McCaffrey was influenced by that decision -- Stanford offered only a brief statement of support from coach David Shaw -- but it should be noted that Fournette is still healing from an ankle injury, while McCaffrey was also hurt earlier this year. There would certainly be risk involved in playing one extra game, as demonstrated by Notre Dame linebacker Jaylon Smith's knee injury in last season's Fiesta Bowl.

Christian McCaffrey rushed for 1,603 yards this season with an average of 6.3 yards per carry. He also had 310 receiving yards and 16 total touchdowns. AP Photo/Thomas Boyd

This much is clear: Stanford is suddenly without its centerpiece -- Bryce Love's promotion to featured back has come a game early -- and there's now some thought that pre-bowl departures might become a trend among college football stars.

It's also the official end of a remarkable era: McCaffrey's 6,191 all-purpose yards since 2015 are the most by any player over a two-year stretch in FBS history.

The NFL draft might have never seen the likes of a Swiss Army knife-like player this versatile, and that will certainly fuel plentiful fascination about McCaffrey's positioning in its pecking order -- and his fit at the next level -- over the next several months.

It's clear that McCaffrey fit remarkably well in college ball, despite reservations when he first stepped foot on Stanford's campus as a freshman just 2½ years ago.

"I was a curious kid, very quiet," McCaffrey said. "That's how I was when I came here. I really just wanted to put my head down and get to work. [Looking back] I would have just told myself to relax a little more and know that everything is going to be OK, because I was pretty stressed when I came here. I didn't know what to expect, just like any new college kid, but it all ended up OK."

The ending there is, of course, an understatement. McCaffrey shattered Barry Sanders' NCAA single-season record for all-purpose yardage in 2015.

"That," Shaw opined, "was the best singular year in the history of college football -- without debate."

ESPN

But there's a strong argument to be made that McCaffrey's 2016 campaign -- despite a lower total statistical output -- was even more impressive in the eyes of NFL scouts. He averaged 6.3 yards per carry this season, up front 6.0 in 2015.

This came in the presence of a less-talented supporting cast. Linemen Joshua Garnett and Kyle Murphy were gone to the NFL, as was quarterback Kevin Hogan and tight end Austin Hooper. Fullback Daniel Marx was also hurt for most of this season. Yet McCaffrey still rushed for 575 yards after contact in 2016, more than his total of 573 yards after contact in 2015 -- despite 84 fewer carries.

According to ESPN Stats & Information data, McCaffrey's average increased from 1.7 yards after contact to 2.3 in 2016.

Gains like these underscored the significant strength increase that McCaffrey made in the offseason. Aside from allowing him to take over and excel as Stanford's short-yardage running back, it demonstrated his physical readiness for the rugged style of the next level.

"There's nothing more he can put on film," Shaw said.

And that truth ultimately led to Monday's announcement, which ended McCaffrey's college career one game early.

He accounted for 45.7 percent of Stanford's touches over the past two seasons and accumulated 573 total touches over that span, both figures that lead the nation. That's an astounding usage rate, and McCaffrey would rather not rack up any more mileage before turning pro.

He thinks the time is right for the NFL experiment to begin, and the possibilities therein are plentiful. Will McCaffrey continue as an every-down back or will his exceptional pass-catching ability -- he racked up 1,206 receiving yards at Stanford -- encourage a team to move him to the slot? Will McCaffrey continue to dazzle with his versatility or will the pros ask him to focus on becoming a deadly return specialist?

One reporter, searching for clues to answer some of these questions after what turned out to be McCaffrey's final college practice, asked the running back about his favorite type of scoring play:

Was the preferred variety a rough-and-tumble cut through tackles in short yardage or was it a longer type -- such as his 90-yard score against California?

McCaffrey, true to his multifaceted on-field form, stayed versatile until the end.

"They're all fun," he grinned. "I mean, I still had to break a few tackles on the 90-yarder."