A lefthanded Dominican, Valdéz was a late call-up in 2018 by the Astros who had a 4-1 record and 2.19 ERA in eight appearances (five starts). His second visit to the majors went quite differently as he went from starting to the bullpen and then back to the minors due to control and temper issues. He went 4-7 in 2019 with a 5.86 ERA in 26 games (eight starts). He will again be tried by the Astros in 2020 as either a starting pitcher or lefthanded relief option.