César Valdez, a right-handed pitcher from the Dominican Republic, embarked on a professional baseball journey that saw him traverse multiple leagues and teams. Born on March 17, 1985, in Santo Domingo, Valdez began his career in Major League Baseball (MLB) with the Arizona Diamondbacks. He made his MLB debut on May 3, 2010, against the Houston Astros. During his initial stint with the Diamondbacks, Valdez appeared in nine games, starting two of them. His time in the major leagues was brief, and he spent the following years honing his skills in various minor league systems.

After his initial MLB experience, Valdez's career took him across different countries and leagues. He played in the Mexican League, where he found a degree of success that kept him in the game. His performances in Mexico were instrumental in keeping his professional career alive, as he continued to develop his pitching repertoire.

Valdez also spent time in the Venezuelan Professional Baseball League, where he further showcased his abilities. His international experience was extensive, and he became known for his adaptability and perseverance. Despite the challenges of maintaining a career across different leagues, Valdez continued to pursue opportunities to return to the MLB.

In 2017, Valdez made a return to the major leagues with the Oakland Athletics. He appeared in four games for the Athletics, starting two of them. Later that year, he was traded to the Toronto Blue Jays, where he pitched in nine games. His time with the Blue Jays marked his last appearance in the MLB during that period.

Valdez's career took another turn as he continued to play in the Mexican League and other international circuits. His persistence paid off when he returned to the MLB with the Baltimore Orioles in 2020. During the pandemic-shortened season, Valdez emerged as a reliable option out of the bullpen for the Orioles. He pitched in nine games, recording a 1.26 ERA and earning three saves. His performance in 2020 earned him a spot on the Orioles' roster for the 2021 season.

In 2021, Valdez continued to pitch for the Orioles, appearing in 39 games. He served primarily as a reliever, and while his ERA rose to 5.87, he managed to record eight saves. His role with the Orioles highlighted his ability to adapt and contribute to the team's bullpen needs.