The injury actually seemed to happen before the collision. McCann was trying to beat second baseman Josh Harrison's throw on a fifth-inning bouncer, but the throw led Jaso into McCann's path as he reached to grab the ball.
As Jaso reached for the ball behind first base, McCann came up on the bag. Replay showed his right foot hit the side of the bag and he turned his ankle.
McCann tumbled to the ground behind the bag as first-base umpire Gabe Morales ruled him out. McCann walked off the field under his own power, followed by head athletic trainer Kevin Rand. Backup Jarrod Saltalamacchia replaced McCann behind the plate in the sixth inning.
Jason Beck is a reporter for MLB.com. Read Beck's Blog, follow him on Twitter @beckjason and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.