Fernandez is hitting .277 with a .320 on-base percentage and five home runs in 201 plate appearances for Double-A Hartford.
Fernandez was optioned to Double-A Hartford on Friday, Thomas Harding of MLB.com reports.
The Rockies selected Fernandez to their 40-man roster Tuesday.
Fernandez has gone 5-for-12 with three doubles, two walks, three RBI and two runs in three games for Double-A Hartford since returning from the 7-day injured list Saturday after missing time with an unspecified injury.
Fernandez went 1-for-4 with a home run and two strikeouts in his debut for Double-A Hartford on Tuesday.
Fernandez hit .385 with 10 home runs and 19 strikeouts over 28 games in May for High-A Spokane.