Mark Helfrich

Former Oregon head coach Mark Helfrich is a candidate for Auburn's offensive coordinator position. (AP Photo/Thomas Boyd)

As the second day of Auburn's offensive coordinator search comes to a close, there have been some developments among potential candidates, including former Oregon coach Mark Helfrich.

A source told AL.com that Helfrich, who was fired after going 4-8 in his fourth season as Oregon head coach, is waiting on a head coaching job and would be highly unlikely to take the offensive coordinator position if it were offered by Auburn's Gus Malzahn.

While message boards run rampant with rumors as to Helfrich's whereabouts, his willingness to wait for a head coaching job in the future - he's due a buyout of $11.6 million over the next three years from Oregon - could be put to the test as all FBS head coaching positions are filled. The last vacancy was filled Friday with former Western Michigan quarterback Tim Lester taking over at his alma mater for P.J. Fleck, who left for Minnesota.

Helfrich, who was 37-16 as head coach for the Ducks, has not called plays since he was offensive coordinator at Colorado in 2008. Chip Kelly called Oregon's plays as head coach from 2009-12 and Helfrich gave offensive coordinators Scott Frost (2013-15) and Matt Lubick (2016) play-calling duties.

If Helfrich were to change his mind and accept an offer to be Auburn's offensive coordinator, it's unclear whether he would return to calling plays, as Rhett Lashlee did for the final 10 games of 2016 or if offensive line coach Herb Hand would have that sole responsibility, making Helfrich essentially the quarterbacks coach.

Helfrich's understandable preference to be a head coach could also be viewed as the equivalent of what Auburn did when it hired Will Muschamp as defensive coordinator and made his contract easy to walk away from without a buyout after just one year. Doing the same for Helfrich, who unlike Muschamp's buyout from Florida has an offset in his buyout from Oregon, could create instability were he to come to Auburn and leave for a head coaching job after just one year.

Helfrich does have a longer track record of coaching quarterbacks than some of Auburn's other potential candidates, having coached Heisman Trophy winner Marcus Mariota at Oregon and Arizona State record-setting quarterback Andrew Walter among others.

Another source told AL.com Auburn's next offensive coordinator might not end up having any direct ties to Malzahn and a coach with a longer track record may be preferred, which would bode well for Helfrich but not for other potential candidates.

While Arizona State offensive coordinator and former Auburn analyst and Spain Park coach Chip Lindsey led Southern Miss to a top 15 ranking in total and scoring offense in 2015, his tenure as an FBS coordinator is only three years.

Eliah Drinkwitz, who was Malzahn's running backs coach at Arkansas State in 2012, has been an offensive coordinator for just two years while at Boise State (2015) and North Carolina State this past season.

Cal offensive coordinator Jake Spavital, who worked with Malzahn and Hand at Tulsa in 2008, has agreed to become the offensive coordinator at West Virginia, according to FOX Sports' Bruce Feldman.

If Malzahn were to go with a veteran offensive coordinator, one name that has surfaced as a potential candidate is Kentucky's Eddie Gran, who served as Auburn's running backs and special teams coach from 1999-2008.

While Gran, who is making $650,000 at Kentucky, has a distinguished record as an offensive coach and play-caller, his background is as a running backs and wide receivers coach. If Gran were to return to Auburn, it would likely lead to either shuffling of positions on the staff or additional changes to fill the void at quarterbacks coach.

The same could be said of Clemson's Jeff Scott, who has only coached wide receivers and not been the team's play-caller, a responsibility of Tony Elliott, whose background is as a running backs and wide receivers coach.