Herrera spent another season with High-A Modesto, but considering he only batted .260 last season, he'll likely head back to the minors for more seasoning after spring training.
Patterson has torn up the minor leagues and even reached Double-A in his third professional season. That being said, he'll likely head back to the minors after spring training to get more work against advanced pitchers.
Dahl reached Double-A for the first time in 2015, and although he slugged .417, he struck out a ton. He'll likely head back to the minors after spring training for more seasoning.
Williams spent most of 2015 in Double-A in the Giants organization, but he did get a short taste of the majors in September. Despite this, it'll be tough to crack the 25-man roster out of spring training with Nick Hundley, Tom Murphy, and Dustin Garneau in the way.
Swanner spent 2015 with Double-A New Britain and showed off his power with 17 home runs. Although the invitation is promising, he'll likely start the season in the minors to develop more.
Nunez caught at Low-A Asheville last season, posting an .821 OPS thanks to 13 home runs. The invitation is nice, but he'll likely head back down to the minors after spring training concludes to develop more.
Casteel was fairly successful at the Triple-A level last season, hitting .292 despite striking out nearly 25 percent of the time. He could be knocking on the door of the majors soon, but he may have to wait with the catcher pecking order in the majors pretty well set already.
Schlepper appeared in the majors with the Cubs the last two seasons, but he struggled both times, most recently to the tune of a 7.36 ERA. He'll need to improve against major league hitters if he wants to garner a spot in the Colorado bullpen.
Huntzinger spent the last three seasons at the Triple-A level, and last season definitely wasn't promising, either. He posted a 4.63 ERA in 56.1 innings pitched, meaning he'll have to vastly improve if he wants a chance to pitch with the Rockies after spring training.
One of the top prospects in the Rockies organization after being acquired in the Troy Tulowitzki deal, Hoffman pitched well at the Double-A level. Although he shows promise, he'll likely head back to the minors after spring training to pitch more against upper-level hitters.