Carle, 23, posted a 3.67 ERA across two minor league stops in 2014, topping out at High-A Bradenton. The Pirates' 2013 10th-round pick struck out only 5.3 batters per nine innings in his first pro season but issued just 22 walks in 137⅓ frames.
Those statistics alone point to Carle being the type of pitcher the Rockies like, an assumption that is only given more weight by looking at his near-50 percent ground ball rate that is helped by a sinker that sits in the upper 80s/low 90s and tops out at 94 mph. His secondary pitches -- a slider and change-up -- are fringy at best, according to Tim Williams' profile of Carle at Pirates Prospects.
Carle, an alumnus of Long Beach State, was ranked as 340th-best amateur prospect prior to the 2013 MLB Draft.
Scahill, a 27-year-old right-hander, appeared in 41 big league games during parts of three seasons with the Rockies. He posted a 4.42 ERA while striking out 35 batters and walking 21 in 57 innings. Scahill was converted from a starter in 2012 after producing mixed results since being drafted in the eighth round in 2009.
The Rockies designated Scahill for assignment on Nov. 3 to make room for reliever Jorge Rondon, who was claimed off of waivers from the Cardinals that same day.