Arraez was diagnosed with a Grade 1 right ankle sprain after undergoing an MRI on Sunday, Betsy Helfand of the St. Paul Pioneer Press reports.
The MRI confirmed that the rookie avoided major damage to his ankle after he was carted off the field in Saturday's 4-3 win over the Royals, but the injury nonetheless clouds his availability for the start of the postseason. The Twins will have until Friday to set their roster for the ALDS, giving Arraez some time to heal up and prove that he's fit to play. If Arraez is excluded from the ALDS roster, Jonathan Schoop would likely take over as the Twins' primary option at the keystone.