Strickland, who owns a 1-2 record with a 2.08 ERA this season, was expected to begin serving his punishment on Monday with the opener of a four-game series against the host Atlanta Braves.
Strickland apparently held a grudge after Bryce Harper hit two home runs against him in the 2014 National League Division Series. The 28-year-old took out his frustrations on May 29 when he hit Harper on the right hip with a 95 mph fastball in the eighth inning.
Harper charged the mound and threw his helmet, which appeared to slip out of his hand and come nowhere close to Strickland. They both landed punches before being engulfed by teammates in a melee at the center of the infield.
Harper was initially suspended four games for his role before Major League Baseball reduced his punishment to three.