Griffin popped the question on Lauderdale By the Sea Beach.
Sadeiko, 23, is a track athlete at Florida State. She is also pregnant with the couple's child.
Griffin, 27, is currently a free agent. He was the No. 2 pick overall in the 2012 NFL Draft. Griffin went on to become the 2012 NFL Rookie of the Year. He went 9-6 as a starter in his first season for the Redskins, completing a career-best 65.6 percent of his passes for 3,200 yards, 20 touchdowns and five interceptions.
The 2011 Heisman Trophy winner joined the Browns in 2016 after three seasons with the Redskins. He was cut by the Redskins last offseason. Griffin is 6-19 in his last 25 games as a starter. He completed 59.2 percent of his passes for 886 yards, two touchdowns and three interceptions in five starts for the Browns last season.
The Browns released Griffin on March 10, despite executive vice president Sashi Brown saying that the franchise wasn't taking a "short-term" look at the quarterback before the season began.
2IN1: Today was the happiest day of my life and the last 8 months have been the most exciting time ever. The man of my dreams and love of my life asked me to marry him today and we are one month away from welcoming our beautiful baby into this world. Words can't describe the feelings and emotions... Unreal. I'm the happiest girl alive and so excited about everything ahead❤️💍👼🏽👰🏼 #BestDayEver #Engagement #BabyShower #TooManyEmotions
Sadeiko was a second-team All-American for the Seminoles. She is FSU's school record-holder in heptathlon and pentathlon. She graduated from the school on May 6.