Cleveland Indians Valdéz signed as an international free agent with the
Cleveland Indians on May 29, 2009. He played for the
Dominican Summer League Indians in 2009 and 2010. On May 30, 2012, he signed a minor league contract with the
Washington Nationals.
Texas Rangers On December 21, 2018, Valdéz signed a minor league contract with the
Texas Rangers. He was assigned to the
Nashville Sounds to open the 2019 season. With Nashville in 2019, he went 1–7 with a 4.92 ERA over innings. On June 8, Valdéz had his contract selected and he was called up to the major leagues for the first time, as the 26th man of a
doubleheader versus the
Oakland Athletics. He made his debut that afternoon, throwing two scoreless innings in relief. With Texas in 2019, Valdéz went 0–0 with a 3.94 ERA and 18 strikeouts over 16 innings. On November 1, 2019, Valdéz was claimed off waivers by the
Seattle Mariners.
Boston Red Sox On February 23, 2020, Valdéz was claimed off waivers by the
Boston Red Sox. He was optioned to the
Triple-A Pawtucket Red Sox on March 8. On July 24, Valdéz made his Red Sox debut in the opening game of the delayed-start season, pitching two scoreless innings of relief in a 13–2 win over the
Baltimore Orioles. On August 25, Valdéz pitched scoreless innings to pick up his first MLB win in a 9–7 victory over the
Toronto Blue Jays. Overall with the
2020 Red Sox, Valdéz appeared in 24 games, all in relief, compiling a 1–1 record with 3.26 ERA and 30 strikeouts in innings pitched. On June 6, he recorded his first major league
save, coming in extra-innings away game against the
New York Yankees after
closer Matt Barnes had a
blown save in the bottom of the ninth. Valdéz was optioned to the Triple-A
Worcester Red Sox on June 10, after pitching three times in four days. He was recalled to Boston on July 23, returned to Worcester on August 12, and again recalled to Boston on August 30. On September 12, Valdéz was placed on the COVID-related list. Overall during the regular season, Valdéz made 28 relief appearances for Boston, pitching to a 2–0 record with 5.85 ERA while striking out 35 batters in 40 innings. He subsequently split time between Worcester and Boston, being recalled and optioned multiple times. Valdéz was
designated for assignment on July 26. In 13 relief appearances with Boston during 2022, he posted a 4.41 ERA and 0–1 record while striking out 13 batters in innings.
Seattle Mariners On July 29, 2022, Valdéz was claimed off waivers by the
Seattle Mariners and was optioned to the Triple-A
Tacoma Rainiers. In 18 appearances for Tacoma, he logged a 4.22 ERA with 16 strikeouts in innings of work. On September 30, Valdez was designated for assignment following the promotion of
Brian O'Keefe. He cleared waivers and was sent outright to Triple–A Tacoma on October 3. Valdez elected free agency following the season on November 10.
Colorado Rockies On December 15, 2022, Valdéz signed a minor league contract with the
Colorado Rockies. In 22 games (15 starts) for the Triple–A
Albuquerque Isotopes, he registered a 5–7 record and 8.15 ERA with 49 strikeouts in innings pitched. On August 15, 2023, Valdéz was released by the Rockies organization.
Toros de Tijuana On April 17, 2024, Valdéz signed with the
Toros de Tijuana of the
Mexican League. In 2 starts for Tijuana, Valdéz logged a 3.72 ERA with 5 strikeouts across innings pitched.
El Águila de Veracruz On April 27, 2024, Valdéz was traded to the
El Águila de Veracruz of the
Mexican League. In 14 starts for Veracruz, he logged a 6–5 record and 4.68 ERA with 30 strikeouts across innings pitched.
Toros de Tijuana (second stint) On September 20, 2024, Valdéz was traded back to the
Toros de Tijuana of the
Mexican League. Valdéz made nine appearances (two starts) for Tijuana in 2025, posting a 1-0 record and 3.60 ERA with 12 strikeouts over 15 innings of work.
Bravos de León On May 29, 2025, Valdéz,
Danny Ortiz, and
Andrew Bellatti were traded to the
Bravos de León in exchange for
Aderlin Rodríguez. He did not appear in a game for León. ==Personal life==