In three seasons, Hornibrook has a 60.5 completion percentage, 155 passing yards per game and 47 touchdown passes with 33 interceptions.
Hornibrook is set to graduate in May and will have one year of immediate eligibility remaining.
Florida State has finally solved its quarterback depth problem for 2019.
Since the tumultuous departure of Deondre Francois, FSU has been desperately pursuing help at the quarterback position.
The addition of Hornibrook will put a bit of pressure on projected starter and redshirt sophomore James Blackman. Florida State is coming off a disappointing season in which it finished with a 5-7 record. Hornibrook missed four games with a concussion, and threw nearly as many interceptions (11) as touchdowns (13).
The last time the Seminoles brought in a grad transfer QB, there was expectations that Everett Golson was going to pick up where Jameis Winston left off - expectations that were never going to take place even before he missed games following a concussion and eventually left the team.
He logged a career year in 2017, tossing for 2,644 yards, completing 62.3 percent of his passes (198-318) with 25 touchdowns and 15 interceptions.
Longtime Florida State head coach Mike Martin continues to make history in his final season.
Beyond those two, FSU has Louisville transfer Jordan Travis, but he is not expected to eligible in 2019 unless the NCAA grants him a waiver.