Haniger underwent an MRI Saturday, and in his postgame media availability, Seattle manager Scott Servais told reporters that it is a Grade 2 right high ankle sprain.
The Mariners will miss Haniger's offense. Though hitting only .200 this season, the 31-year-old veteran has three home runs and seven RBIs for a team that has been gaining momentum at the plate after a slow start. Even after the loss Saturday, Seattle (11-10) sits in second place in the American League West, and its 95 runs is the second-highest total in the division.
Servais described Haniger as "very sore" after limping off the field following a single Friday in another loss to the Marlins. Haniger began his Saturday with the MRI, then joined his teammates at the ballpark before the exam's results came in.
"He's going to be out a little while," Servais said. "We'll have to wait to see how he responds to treatments, get the swelling down, get the range of motion going back and see where it takes us."
It's another roadblock for the outfielder, who also spent time on the COVID-19 injured list this season, and has played in just nine games. A right fielder in his fourth season in the majors, Haniger sports a .262 career batting average to go along with 104 home runs and 296 RBIs.
The Mariners brought back outfielder Stuart Fairchild from their Triple-A affiliate in Tacoma, Washington, to take Haniger's place on the roster.
Seattle also dealt infielder-outfielder Mike Ford to the San Francisco Giants for cash considerations Saturday. The 29-year-old Ford signed a minor league deal with Seattle last month and began the season in Tacoma. The Mariners promoted Ford to the major league club April 19 before he was designated for assignment Monday.
The Associated Press contributed to this report.