Nieves will be in uniform and available for Friday night's game at Cincinnati. The Rockies also transferred infielder Hector Gomez (groin strain) from the 15-day disabled list to the 60-day DL; their 40-man roster remains full.
Hernandez has been dealing with tendinitis in his left hand, a condition that has affected his ability to grip a bat. Overall this season, the 36-year-old backstop is batting .215 with a .260 on-base percentage and a .398 slugging percentage. He last started on Wednesday in Miami and has played in 27 of Colorado's 43 games this season.
Nieves, who will wear No. 41, began the season with Colorado Springs and has hit .299 with four doubles, three homers, 14 RBIs and 14 runs scored in 28 games at Triple-A. This will be the 34-year-old's fifth Major League team since 2002, as he previously played with the Padres, Yankees, Nationals and Brewers.
Nieves is a career .221 hitter with 32 doubles, two triples, five homers and 73 RBIs in 282 Major League games.