Tom Brady is expressing his grief following the death of his former teammate Ryan Mallett.

"We lost a great man," the seven-time Super Bowl champion wrote on his Instagram Stories June 27 alongside a photo of the duo from their time on the New England Patriots. "Praying for the Mallett family and all their loved ones tonight." 

Mallett—who was a quarterback and served as a backup for Brady—died in an apparent drowning off a Florida Gulf Coast beach on June 27, according to the Okaloosa County Sheriff's Office. He was 35 years old. 

The Sheriff's Office said first responders were called to a beach in Destin at around 2:12 p.m. that day.

"A group of people in the water near the second sandbar had reportedly been struggling to make their way back to shore," the department said in a statement posted to Facebook. "One of the individuals, an adult male, went under and lifeguards say he was not breathing when pulled out."

While the authorities said "lifesaving measures were immediately undertaken," they noted that the man, who was later identified as Mallett, was pronounced dead at the Destin Emergency Room. An official cause of death has yet to be revealed.

Born in Arkansas, Mallett started his college football career on the University of Michigan Wolverines and later joined the University of Arkansas Razorbacks. He was drafted into the NFL in 2011 and played for the Patriots for the 2012-2013 season. The athlete was then a member of the Houston Texans from 2014 to 2015 and went on to compete with the Baltimore Ravens from 2015 to 2017.  

In addition to Brady, several members of the NFL community paid their respects after learning of Mallett's death.

"I am extremely saddened by Ryan's tragic passing," Patriots head coach Bill Belichick said in a statement shared on social media. "My thoughts and prayers are with his family and the many people whose lives he touched."

Added the Texans' official Twitter account, "Our thoughts and prayers are with the Mallett family."

Ravens Head coach John Harbaugh also shared what he'll remember about the late football player.

"Ryan was a part of us," he noted in a statement posted to the organization's website. "I will always remember the love he had for his teammates and for making the most of, and enjoying every football day while here. Once a Raven always a Raven, R.I.P. Ryan."

Before Mallett died, he was a coach in Arkansas' White Hall School District. 

"Coach Mallett was a beloved coach and educator," the school said in a statement posted on Facebook. "We ask that you remember his family, team, students, fellow coaches, and the White Hall School District staff in your prayers."

For the latest breaking news updates, click here to download the E! News App