Turner was hit in the wrist by a 96-mph fastball from reliever Pedro Strop in the seventh inning of Washington's 5-4 loss to the Cubs on Thursday. X-rays confirmed the break. The Nationals did not give a timetable for Turner's return to the team.
"It sucks," Turner said Thursday. "I'm trying to have a good at-bat right there. You wish it hit you in the back or arm or something -- not the hand or wrist, which is never fun. ... It is what it is, you have to roll with it."
The Nationals called up Adrian Sanchez from Triple-A Syracuse and transferred left-handed pitcher Sammy Solis (elbow inflammation) to the 60-day disabled list on Friday.
Turner's injury is a huge blow to the first-place Nationals, who lost original leadoff man Adam Eaton on April 28 to a torn ACL.
The runner-up in last year's NL Rookie of the Year voting, Turner tied a franchise record Tuesday when he stole four bases against the Cubs. He swiped two more Thursday, giving him 22 steals in June, and a major league-leading 35 on the season.
His 22 steals this month were the most by a Nationals/Expos player in any month since Tim Raines in August 1984 (23).
Sanchez is being called up to the majors for the first time and can play three infield positions as well as the outfield. The 26-year-old has spent 10 seasons in the organization, playing a total of 914 minor league games.
ESPN's Eddie Matz contributed to this report.