|Chicago White Sox – No. 29|
|Pitcher \ Bullpen coach|
|Born: December 29, 1964|
Curtis Allan Hasler (born December 29, 1964) is an American professional baseball coach and former pitcher. He has served as the bullpen coach for the Chicago White Sox of Major League Baseball since 2017.
Hasler is a native of Honolulu who has spent his entire professional career in the White Sox organization. A 6 ft 7 in (2.01 m), 215 lb (98 kg) right-handed pitcher, he attended Bradley University and was selected by the ChiSox in the 21st round of the 1987 Major League Baseball Draft. He pitched for five seasons (1987–91) in the club's farm system, posting a win–loss record of 34–30 and an earned run average of 3.51 in 97 minor-league games and 5612⁄3 innings pitched. He appeared in 11 games at the Triple-A level in his final active season.
In 1992, he became a pitching coach at the Rookie and Class A levels in the White Sox' system, and continued in that role until he became roving minor league pitching coordinator from 2011–16. The 2017 season marked his 30th year in the Chicago organization and his first in the Major Leagues as bullpen coach on the staff of Rick Renteria.
- Merkin, Scott (October 14, 2016). "McEwing named bench coach amid staff changes". whitesox.com. Retrieved October 17, 2016.
- Career statistics and player information from MLB, or The Baseball Cube, or Baseball-Reference (Minors)
| Chicago White Sox bullpen coach