Doolittle made 463 relief appearances across 11 seasons, spending more than half his time in MLB with the Oakland A's
A perfect Sean Doolittle has middle innings set for Washington Nationals - Federal Baseball
Doolittle announces retirement after 11 MLB seasons - Blog
A's Pitcher Sean Doolittle Turns Plan B Into Good Career Move - The New York Times
All-Star reliever Sean Doolittle retires after 11 seasons - Field Level Media - Professional sports content solutions
MASN Nationals
Reliever Sean Doolittle announces MLB retirement after 11 seasons – NBC Sports Bay Area & California
Nationals pitcher Sean Doolittle announces his retirement after more than a decade in the majors
Sean Doolittle Announces Retirement After 11 Seasons in MLB