"He said, 'You've got to stop doing this.' He led it on for a good five minutes," said McMahon, the club's No. 3-ranked prospect per MLBPipeline.com. "I'm sitting there and I'm like, 'Come on, I get it. I messed up.' And then he dropped it on me. So it was cool."
The Rockies announced prior to Friday's series opener in Miami that they selected the contract of McMahon and optioned outfielder Raimel Tapia to Triple-A Albuquerque.
Rated the No. 64 overall prospect, McMahon has mashed between Triple-A and Double-A Hartford this year. He hit .375 with 13 homers in 59 games for the Isotopes, compiling a .354 mark and 19 homers in 108 total games in the Minors.
McMahon joins Colorado as it fights to stay atop the National League Wild Card standings. The Rockies entered Friday one game ahead of the D-backs for the top spot.
"Just hop on board and go along for the ride and try to contribute however you can," McMahon said. "This is the stuff everyone wants to be a part of."
Rockies manager Bud Black said McMahon will primarily play first base, but his ability to handle both second and third is a plus. Expect the left-handed batter to receive plenty of pinch-hitting opportunities and start every once in a while.
"We're excited for Ryan as he goes into this series here," Black said. "He gives us some versatility in the infield, and he gives us a nice left-handed -- potentially productive -- bat when he plays or pinch-hits."
Until Ian Desmond returns from the disabled list, Black said McMahon is an insurance player behind Mark Reynolds, who returned to Friday night's lineup after injuring his left hand earlier this week.
Not every team, especially one vying for a postseason berth, has the luxury of calling up someone like McMahon.
With a swing described as smooth and sweet, McMahon has produced at essentially every level in the Minors since Colorado selected him in the second round of the 2013 Draft.
Over his last 14 games at Albuquerque, McMahon hit .400 with four homers, four doubles and one triple. Black and the Rockies' player development staff felt he had done everything possible to earn the callup.
"He's performing," Black said. "What he did at Double-A and Triple-A all season long has been impressive."
Patrick Pinak is a reporter for MLB.com based in Miami. This story was not subject to the approval of Major League Baseball or its clubs.