The Yankees and Mariners had been warned earlier in the contest, stemming from an incident in the fifth inning, when Yankees first baseman Josh Phelps collided with Mariners catcher Kenji Johjima on a potential play at the plate.
In his next at-bat, in the sixth inning, Phelps was hit in the back by a pitch from Mariners starter Jarrod Washburn, prompting home-plate umpire Mike Everitt to point to both benches in warning.
Proctor's first pitch to Betancourt was a fastball behind the shortstop. Betancourt pointed his bat at Proctor before being held back by Yankees catcher Wil Nieves, while Proctor gestured for Betancourt to come out to the mound.
As both benches emptied, Everitt intercepted Proctor and relievers raced in from both bullpens, creating a brief skirmish near the home-plate area. Left-hander Sean Henn replaced Proctor and walked Betancourt.
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.