Lamet was part of the package the Milwaukee Brewers received Monday in the trade that sent four-time All-Star closer Josh Hader to the San Diego Padres. The Brewers announced two days later that they had designated Lamet for assignment.
The Rockies announced Friday they had claimed Lamet and designated right-hander Ashton Goudeau for assignment.
Lamet went 3-1 with a 2.09 ERA and finished fourth in the NL Cy Young Award voting during the pandemic-shortened 2020 season, but he has struggled since while dealing with injuries. The 30-year-old Lamet had an 0-1 with a 9.49 ERA in 13 relief appearances for the Padres this season.
The Brewers also received reliever Taylor Rogers, outfield prospect Esteury Rodriguez and pitching prospect Robert Gasser in the Hader trade.
After the Hader trade, the Brewers brought in reliever Matt Bush on Monday from the Texas Rangers for two minor leaguers, left-hander Antoine Kelly and utilityman Mark Mathias. They then acquired reliever Trevor Rosenthal from the San Francisco Giants on Tuesday.
"Dinelson has a good arm and was included in the trade to help balance out the deal," Brewers president of baseball operations David Stearns said Wednesday. "As subsequent transactions played out, the roster fit became a little tougher. We are hopeful we will be able to keep him in our system."