He played from 2010 through 2014 in the Cubs' farm system, where he was named to the Florida State League mid-season All-Star team in 2014,[1] while leading the Class A-Advanced Daytona Cubs with seven triples and 22 stolen bases, hitting .270 (119-for-441) with 13 doubles, three home runs, and 55 RBI in 122 games.

[2] Hernández was acquired by Boston as the player to be named later in the deal that sent Félix Doubront to the Cubs in August 2014.

[2] Hernández was added to the Red Sox' 40-man roster in November 2015, and made a strong impression at 2016 spring training at JetBlue Park.

[6] Hernández made his MLB debut on April 17, 2016, collecting a hit and a walk with one run scored.

[7] He split time between Pawtucket and Boston during the season, and hit his first MLB home run on Memorial Day, May 30, against the Baltimore Orioles.

In 2017, Hernández sustained a left shoulder subluxation in a game in early May, and was added to the disabled list.

[24] On January 6, 2021, it was announced that Hernández had been signed to a minor-league contract by the Chicago White Sox and was invited to spring training.