Riley Ferguson in an interview this spring (photo by Evan Woodbery)

KNOXVILLE, Tennessee — Riley Ferguson has been the perfect subject for that segment of the fan base prone to extreme and sudden swings of emotion.

A few weeks ago, according to some, he was the best the quarterback on the team. (His main qualification for that honor was that he was the only who had yet to take a college snap.)

Today, just as many contend that his departure is no big deal, and the Vols will be fine without him.

In fact, when he surprised coaches with the news that he didn’t plan to return to Knoxville, Ferguson still had a shot of winning the starting quarterback job. Despite a bumpy spring, I still think he had the best chance of any of the three competitors vying to unseat senior Justin Worley.

That’s what makes his departure so stunning. Coaches had invested a lot of time and effort into his development for a reason. They thought — and still think — he could be a good SEC quarterback. And now he appears to be ready to transfer to a lower-division team without even taking a snap?

Ferguson hasn’t returned a request for comment, so we haven’t heard his side of his decision to transfer. But he apparently indicated to coaches that he felt more comfortable back home.

Twitter myths notwithstanding, coaches didn’t “run off” Ferguson. They wanted him to stay. In fact, Butch Jones has carefully parsed every comment he makes about the quarterback situation with the express intent of discouraging anyone from transferring.

Ferguson did not arrive on campus with the same maturity as, say, Joshua Dobbs. Ferguson was high-maintenance. And he was certainly not out of quarterback central casting like his three other colleagues. But he had enough natural talent that coaches were to work with his strengths while they tried to fix his flaws.

If one quarterback seizes the reins of the offense this spring and stays healthy, Ferguson might be largely forgotten by November. But if the Vols suffer a rash of injuries  (like they did in 2013) or if none of the quarterbacks perform consistently (again, see 2013) then the loss of the inscrutable but talented Ferguson will really sting.