As part of Wednesday’s trade, the teams exchanged international bonus money slots for the signing period that starts July 2, with the Cubs getting No. 74 and the Rockies No. 28.
Butler was designated for assignment Saturday after going 6-16 with a 6.50 ERA in 36 career games with the Rockies. The 25-year-old was the 46th overall pick in the 2012 amateur draft.
Farris split time last season between Class A Myrtle Beach and Double-A Tennessee. He was picked by the Cubs in the ninth round in 2014.
The 24-year-old is 4-13 with a 2.91 ERA during three minor league seasons. He has 38 walks and 151 strikeouts.