NEW YORK — Former Rockies infielder DJ LeMahieu and Yankees teammate Luis Cessa tested positive for the coronavirus, New York manager Aaron Boone said Saturday. Both tested positive before traveling to New York and are self-isolating at home, according to Boone. It was all part of a rough day for the Yankees that included Masahiro Tanaka crumpled motionless on the mound after being hit by a hard line drive off the bat of slugger Giancarlo Stanton during practice. Tanaka was alert and sent to a hospital after the incident, a frightening scene moments into the team’s first official summer camp workout. “That took a little air out,” Boone said. LeMahieu and Cessa won’t report until they’ve cleared quarantine.