Rockies will call up Jon Gray for start Tuesday

After trading Troy Tulowitzki to the Blue Jays last week, the Colorado Rockies are getting right to their youth movement and will call up top pitching prospect Jon Gray to start Tuesday against the Mariners, according to MLB.com's Thomas Harding:

#Rockies top pitching prospect RHP Jon Gray will make Majors debut Tuesday vs. #Mariners http://t.co/yzKH7dnu8R pic.twitter.com/dhvlwYbQeR

— Thomas Harding (@harding_at_mlb) August 3, 2015

Gray, the No. 35 prospect in baseball on MLB.com's midseason list, has spent all of 2015 at Triple-A Albuquerque, with a 4.33 ERA in 114⅓ innings with 41 walks and 110 strikeouts. Those numbers are skewed by an ugly April in which Gray allowed 21 earned runs in 17⅔ innings. Since his slow start, Gray has posted a 3.17 ERA in 17 starts and 96⅔ innings with 93 strikeouts in that span. The strikeouts for Gray have jumped of late, as he has struck out 65 in his last 46⅓ innings.

The Rockies will slot Gray into the rotation in place of veteran right-hander Kyle Kendrick, who left his last start in St. Louis after just one inning with a shoulder injury and was subsequently placed on the disabled list, where he joins fellow Rockies starters Chad Bettis, Tyler Chatwood, David Hale and Jordan Lyles.

Gray is the second former first-round pick the Rockies have called up this week, as they promoted 2011 first rounder Kyle Parker on Saturday, though he had been to the majors in 2014 and for a brief stint earlier in 2015 as well.

With Tulowitzki traded and Gray set to debut in the span of eight days, Rockies fans are witnessing a rapid changing of the guard at Coors Field, one that is likely faster than any before in the team's relatively brief history.