He only needed a week following Ohio State's Orange Bowl loss to Clemson to make up his mind, or rather, come to the realization that returning was his only realistic option.
Back with the Buckeyes, Miller's plan should be simple: work on his mechanics, stay healthy and emerge as a leader.
Doing so would dramatically improve his resume ahead of the 2015 NFL draft. In fact, those deficiencies were a big factor in his decision to stay.
But before Miller has a chance to show his growth, where does he stand compared to the other draft-eligible quarterbacks?
Tom Dienhart of the Big Ten Network reviewed the initial 2015 mock drafts, and unsurprisingly, no one is projecting Miller as a first-round selection. Bleacher Report's Matt Miller supported that assessment in his first look at the top prospects.
So where does that put the 21-year-old?
In a ranking of senior quarterbacks from CBS Sports, Miller came in at No. 7. That list, of course, doesn't factor in younger signal-callers such as Marcus Mariota, Jameis Winston and Brett Hundley, all of whom are expected to make themselves available for the draft as likely first-round selections.
In that scenario, Miller would be the 10th-best quarterback.
A total of 14 quarterbacks were taken in this year's draft. The 10th passer off the board was LSU's Zach Mettenberger, who was taken with the second pick in the sixth round by the Tennessee Titans.
In the two years prior, 11 quarterbacks were drafted. B.J. Daniels was the 10th quarterback taken in 2013—selected late in the seventh round—and B.J. Coleman was the 10th in 2012, also selected at the tail end of the final round.
Those numbers line up with what Miller heard when he pondered an early jump to the NFL. According to Bill Raninowitz of The Columbus Dispatch, the NFL Draft Advisory Board told Miller he would be a "mid- to late-round selection."
Of course, he could play his way up the draft board this fall. Doug Lesmerises of The Plain Dealer created a five-part checklist for Miller to become a first-round prospect, with the primary goals of staying healthy and, in general terms, learning more about football.
As of now, though, Miller is projecting as a late-round pick for an NFL team willing to take on a project. The only way for him to change that is with a stellar senior season.
David Regimbal is the lead Ohio State football writer for Bleacher Report.
Follow him on Twitter @davidreg412.