Will Middlebrooks mourns loss of his best friend Ryan Mallett

BOSTON -- The sports world is mourning the loss of former Patriots quarterback Ryan Mallett, who drowned in a tragic accident in Destin, Florida on Tuesday. For former Red Sox third baseman Will Middlebrooks, he lost his "best friend."

Middlebrooks took to social media on Tuesday to mourn the loss of Mallett, sharing several heartfelt tributes to his late friend.

"I lost my best friend today. Someone who has stuck by my side since we were just kids," Middlebrooks said of Mallett, who was just 35 years old. "The most competitive, hard-headed, fun-loving person I ever met. Nothing prepares you for this. I was lucky to have him for as long as I did. Rest in Love One-Five. We love you."  

Middlebrooks and Mallett became friends when the two met at a football camp in Texarkana, Texas in the seventh grade. Their families became close, and Middlebrooks' mom also shared a message about Mallett on social media, calling him her "other son."

"The one who sat on my lap as a joke into adulthood and never, ever forgot my birthday," Julie Procell Middlebrooks wrote. "The other half of [Will Middlebrooks'] competitive soul. I want you back. I want you enjoying the life you made. I want to help your mom and can't."

A third-round pick by the Patriots in 2011, Mallett played in four games with New England during the 2012 season as Tom Brady's backup. Brady paid tribute to Mallett on Instagram on Tuesday night, saying "We lost a great man. Thank you for everything Ryan."

Patriots coach Bill Belichick also released a statement saying that he was "extremely saddened by Ryan's tragic passing."