Aledmys Díaz Serrano (born August 1, 1990) is a Cuban professional baseball utility player who is a free agent.

He has previously played in Major League Baseball (MLB) for the St. Louis Cardinals, Toronto Blue Jays, Houston Astros, and Oakland Athletics.

He played for the Naranjas de Villa Clara in the Cuban National Series from 2007 through 2012, before defecting to the United States.

While growing up in Santa Clara, Cuba, Díaz lived on the same street as, and was friends with, future Major League Baseball (MLB) pitcher José Fernández.

They played for the same youth baseball team, and Díaz's father and uncle encouraged Fernández's mother to bring him to the ballpark.

Fernández commented that had Díaz's uncle not been an influence early in his life, he would not have pursued a professional baseball career.

[8] To audition for a contract with MLB clubs, Díaz held a showcase with fellow Cuban defector Odrisamer Despaigne on February 13, 2014.

[10] Over the full 2015 campaign, Díaz batted .278/.339/.445 with 13 home runs and 52 RBI over 116 total games between Springfield and the Memphis Redbirds of the Triple–A Pacific Coast League.

[14] Originally planning for Díaz to spend the 2016 season in Memphis, the Cardinals eventually moved three veteran players to accommodate him becoming the starting shortstop.

In his first major league at bat in the third inning against the Pittsburgh Pirates, he singled off Jon Niese for his first hit in a 6–5 loss.

[17] Initially, Díaz' presence on the roster gave the Cardinals a capable hitter with upside who could play shortstop[8] and fill a void until the return of Rubén Tejada, who had injured himself late in spring training.

[15] As the season progressed, Díaz' defense notably improved; in the remaining 51 games leading up to the All-Star break, he committed six errors.

[25] On July 21 against Padres in a 5–5 game, Díaz batted against Carlos Villanueva with the bases loaded in the bottom of the ninth inning and, this time, singled home the game-winning run for his first career walk-off hit.

[26] After sustaining a hairline fracture of his thumb during a game against Miami, the Cardinals placed Díaz on the DL on August 1.

[28] Díaz hit his first major league grand slam on September 27, 2016, his first game back after the death of his childhood friend, José Fernández.

[28] Díaz batted .300 in 111 games in his rookie year, with 121 hits, 28 doubles, 17 home runs, 69 RBIs, a .369 OBP, and a .510 SLG.

[35] Díaz began the season as Toronto's starting shortstop with Troy Tulowitzki on the disabled list (DL).

[37] For the season, Díaz hit .263/.303/.453 with 18 home runs and 55 RBIs in 422 at bats in 130 games while playing primarily shortstop.

[34] On November 17, 2018, the Blue Jays traded Díaz to the Houston Astros in exchange for minor league pitcher Trent Thornton.

[34] On June 6, 2021, Díaz suffered a fracture in his left hand on a hit by pitch delivered from Ross Stripling in a game versus the Blue Jays.

[34] In World Series play on October 29, 2021, Díaz hit a single to right field to end the Atlanta Braves' no-hit bid in the eighth inning of Game 3.

[43] He started at third base and homered on June 4 to help lead a 10–3 win over the Kansas City Royals, and added two singles for his first three-hit game of the season.

[48] Díaz hit his second grand slam of the season versus Martín Pérez of the Texas Rangers on August 9, bringing the Astros back from a 4–0 deficit to result in a 7–5 win.

[49] On August 16, Díaz exited a game versus the Chicago White Sox due to a groin injury, and was placed on the 10-day injured list the following day.