On May 3, 2004, for the Single-A Columbus Catfish,[2] Carvajal combined with starter Chuck Tiffany for a seven-inning no-hitter. Tiffany pitched the first five innings followed by Carvajal, who threw the final two innings. He then was selected in the Rule 5 draft by the Milwaukee Brewers on December 13, 2004. On that same day, the Colorado Rockies acquired him for cash or a player to be named later.[1]
Carvajal made his major league debut on April 6, 2005, with the Colorado Rockies,[1] as he became the youngest player in Rockies history at 20 years and 230 days old, beating Jamey Wright's previous record of 21 years and 191 days old. He then spent the whole 2005 season with the Rockies because he was a Rule 5 draft choice; if he had been taken off the roster, the Dodgers would have had the right to claim him back.[1]
On February 16, 2007, Carvajal was claimed off waivers by the New York Mets.[1] He began the year for the Double-A Binghamton Mets, where he was converted to a starter.[2]