Cy Young winner Barry Zito retiring from baseball at 37

Barry Zito, the 2002 American League Cy Young winner who went on to win two World Series titles with the San Francisco Giants, announced his retirement Monday at the age of 37.

Known for his devastating curveball, the lefty began his career with the Oakland Athletics in 2000. He won the Cy Young in 2002, when he went 23-5 with with a 2.75 ERA.

Along with Tim Hudson and Mark Mulder, Zito was a part of Oakland's "Big Three" in the early 2000s, and the team reached the postseason four years in a row from 2000-2003.

Zito moved across the bay after the 2006 season, signing a seven-year, $126 million contract with the San Francisco Giants. His time in San Francisco was marked by inconsistency, finishing 63-80 with a 4.62 ERA.

He was left off the team's postseason roster in 2010, but was a critical piece of the Giants' 2012 championship team. He started an elimination game in both the NLDS and NLCS and got the win in Game 1 of the World Series against the Tigers.

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"Baseball has surely yielded a windfall of material blessings on me and my family, and I am grateful and humbled for those things every day" Zito wrote in an essay for The Players' Tribune. "More than any dollar earned or trophy standing on my shelf, I can thank this game for the life lessons it taught me about enduring pain and struggle and where to turn when I face adversity again."

He sat out the 2014 season after the Giants declined his option, but returned to baseball in 2015, spending the season with the Athletics' Class AAA team. Zito was called up in September, making three starts, including one against Hudson.

"Every single fan out there in the Bay Area played a vital role in my journey, whether it was the cheering fans or the booers," Zito said. "In sports, these two opposites go hand in hand.