The velocity, the upside and the timing of his potential arrival are all reasons why Greene has been chosen by MLB.com to be this year's prospect to watch in the Blue Jays' system.
"Conner was in big league camp and did really well," Blue Jays director of amateur scouting Brian Parker told MLB.com. "They pitched him a couple times over there to get his feet wet, and he did very well. We got a lot of positive feedback on him."
Toronto's new regime seems intent on taking a more patient approach with its prospects. In the past, the Blue Jays occasionally rushed some of their top players to the big leagues, as evidenced last season when Dalton Pompey, Miguel Castro and Roberto Osuna all made the team out of Spring Training.
That won't be happening this year and Greene isn't an immediate candidate to crack a big league roster, but he's someone to watch later in the season. It's doubtful he would crack the rotation this early, but there's an outside chance if the Blue Jays need another power arm in the bullpen late down the stretch Greene becomes the guy.
Last year, former general manager Alex Anthopoulos seemed to bring up Greene's name in almost every media scrum with reporters. He was quick to point out his progress, and it's easy to understand why after Greene displayed a strong mid-90s fastball that could become even faster as he continues to add muscle.
Greene also possesses a plus changeup, but his curveball remains a work in progress and will need to be refined before it can be considered a reliable option at the big league level. In 2015, he went through three levels of the Minor League system, and he's expected to begin this season at Double-A New Hampshire.
"Definitely just physical maturing," Greene said earlier this spring of his goals for the year. "Getting a little bit older and more weight on my body and fastball command."
Gregor Chisholm is a reporter for MLB.com. Follow him on Twitter @gregorMLB and Facebook, and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.