The club said Barker, also an outfielder, could play Tuesday night when the Rockies play the Houston Astros at Coors Field.
Finley, 42, hit .181 with one home run and two RBIs in 43 games. He is a two-time All-Star (1997 and 2000) and five-time Gold Glove Award winner (1995, 1996, 1999, 2000 and 2004). He was the oldest player in Rockies history.
The club has 10 days to trade, release or outright Finley to the minors.
Barker, 27, hit .333 with five home runs for Colorado Springs. The Rockies chose him in the sixth round in 2002.