Butler, a supplemental first-round pick in the 2012 First-Year Player Draft who pitched for Class A Asheville, Class A Advanced Modesto and Double-A Tulsa last year, and Gray, who pitched at Rookie-level Grand Junction and Modesto last season, are ranked among the MLB.com's Top 100 prospects. Gray, out of the University of Oklahoma, is ranked No. 14, and Butler, out of Radford University, is ranked No. 41.
The non-roster pitchers with Major League experience are righties Manuel Corpas (Rockies and Cubs), Nick Masset (Rangers, White Sox and Reds) and Greg Burke (Padres and Mets), and left-hander Pedro Hernandez (White Sox and Twins). Also among the invitees is righty Chris Martin, who was acquired from the Red Sox with lefty Franklin Morales for infielder Jonathan Herrera on Dec. 18.
Michael McKenry, who was drafted by the Rockies in 2006 and made his debut with them in '10 before spending the last three seasons with the Pirates, and Matt McBride, who appeared in 31 games with Colorado in 2012, are the only non-roster catchers with big league experience. Also invited is Tom Murphy, a third-round pick in 2012 and one of the organization's top catching prospects.
Outfielder Jason Pridie (Twins, Mets, Phillies and O's) and infielder Paul Janish (Reds and Braves) are position players with Major League experience.
Here is the full non-roster list:
Pitchers (12): Christian Bergman, Brooks Brown, Burke, Butler, Corpas, Yohan Flande (L), Gray, Hernandez (L), Martin, Masset, Scott Oberg, Josh Sullivan
Infielders (4): Janish, Angelys Nina, Ben Paulsen, Rafael Ynoa
Outfielders (2): Pridie, Tim Wheeler
Catchers (6): Ryan Casteel, Dustin Garneau, McBride, McKenry, Murphy, Jackson Williams