Griffith's father, Shannon, the football coach at Division III Manchester University, tweeted Wednesday night that his son has responded to his name and moved his hands and feet.
He continues to receive antibiotics for his lungs, which were damaged in the accident. Doctors upgraded his condition to serious but stable and believe he'll make a full recovery.
Griffith likely will remain in Sarasota Memorial's Critical Care Unit for the next 24 hours and then be transferred to a regular nursing unit before being discharged in the coming days.
out of his medically induced coma he woke up well is breathing on his own and resting at this present moment. We are still in a Marathon- Shannon Griffith (@MUCoachGriff) March 20, 2014
Griffith was with two teammates and a friend when they were caught in a rip current.
Mitch McCune and Ty Smith, a safety for the Hoosiers, pulled Griffith to shore and McCune performed CPR before paramedics arrived. Griffith was taken to Sarasota Memorial Hospital in critical condition and put in a medically induced coma.
The Sarasota County Sheriff's Department said Griffith was drinking in a hotel room with McCune, Smith and wide receiver Nick Stoner when the four decided to go swimming. McCune denied they had been drinking.
"I don't know how that started," he told The Associated Press.
Griffith, who grew up in Fort Wayne, Ind., redshirted during the 2013 season.
"We are giving praise to God for his strength and still need your prayers," Shannon Griffith tweeted. "We will update in the morning once he is evaluated but this was a big step forward for Isaac. Thanks for all the well wishes and support."