Barry Zito, a Cy Young award-winning pitcher who spent his entire MLB career in the Bay Area, has decided to retire. The 37-year-old made the announcement in an essay for The Player’s Tribune.

In a piece called “What Baseball Taught Me,” the left-hander noted his career achievements and the highs and lows he’s faced. He won the 2002 AL Cy Young as a member of the Oakland A’s and pitched in the 2012 World Series for the San Francisco Giants. But despite these achievements, he wrote that the most fulfilling thing about his life is the fact that he has accepted who he is.

“Beyond all of the achievements, the single thing that fulfills me today is the acceptance of myself as a worthy and valuable person, regardless of what my stature or position in the world was on a given day of my career,” Zito wrote. “Through the ups and downs, accepting myself was by far the hardest thing to achieve over the last 15 years. I believe it is a battle we all face as we are taught to buy into the ravenous lie that any great success, short-lived fame or bank account will bring us the deep fulfillment we are searching for.”

Later, he wrote that he is retiring from the game and called his September call-up by the A’s the “cherry on top.” But at the end of the piece, he revealed that he is going to try his hand at songwriting.

“I’m retiring today from baseball, but I’ll never be too far away from the game that made me who I am,” Zito wrote. “I am beyond thankful to be at peace with walking away, thanks in large part to my year of renewal in Nashville with the Sounds. My return to Oakland last month was a “cherry on top” moment in my life that my family and I will never forget. I will no doubt be in the stands on both sides of the Bay in years to come.”

Zito was drafted by the A’s in 2000 and won the AL Cy Young just two years later when he went 23-5. In 2007, he went to the Giants and injuries kept him from reaching the heights of his earlier career. His last taste of glory came in 2012, when he had a 15-8 record and did pitch for the Giants in the World Series that year.

He finished his career with a 165-143 record and a 4.04 career ERA.