Wallner will be optioned to Triple-A St. Paul on Monday, Aaron Gleeman of The Athletic reports.
Wallner joined the big-league club Tuesday and went 7-for-11 with a homer, a double, four RBI and two runs over five games with the Twins. However, he'll head back to the minors since Max Kepler (hamstring) and Royce Lewis (knee) are set to be reinstated from the injured list Monday.