12:21 PM PT -- Zak just released a statement on his hospitalization ... saying he was admitted after "not feeling right" and undergoing tests on Friday.
"I have had a bit of a setback these past couple of weeks," Zak said via Kirk's Twitter account.
Zak added he is appreciative of the experienced cardiologists who are looking after him ... and he will have more testing done to make sure he can get back to 100%.
"I appreciate the overwhelming support over the past couple of days," Zak added. "I am feeling good and hope to be out of the hospital soon."
Kirk Herbstreit's son, Zak -- a junior tight end for the Ohio State Buckeyes football team -- was hospitalized Tuesday with an undisclosed health issue, the school announced.
Details surrounding the situation have not been disclosed ... but officials described Zak's condition as "stable," and said he is being monitored and evaluated at OSU's Wexner Medical Center.
The ESPN analyst spoke about the news to ABC 6 in Columbus ... saying, "His family is with him and appreciate everyone's concerns and prayers."
Zak is a third-generation Buckeye -- his dad and grandfather, Jim, were both captains for the Buckeyes. His mother, Alison, was also a cheerleader at OSU.
Zak was recently featured in a Father's Day video with his OSU teammates ... where he gave a special shout-out to his dad.
Love you Zak!!! So proud of you!! https://t.co/1l1vXjPAMr
— Kirk Herbstreit (@KirkHerbstreit) June 18, 2023
"This journey hasn't been easy for me, but you have been there every step of the way. I just want to thank you from the bottom of my heart. I love you."
Kirk responded ... saying, "Love you Zak!!! So proud of you!!"
Originally Published -- 10:26 AM PT