The Twins outfielder had been playing through the injury since April.
Buxton missed 39 games with a hip strain.
A nine-run first inning led Kansas City to a 14-5 victory.
Baltimore had lost 16 straight to the Twins and 14 straight overall.
Yermin Mercedes' ninth-inning bomb drew criticism on Monday night.
The White Sox hammered the Twins 16-4 but Astudillo took the mound in the ninth.
Byron Buxton left the game in the ninth inning with an apparent injury.
Minnesota was two homers shy of tying the single-game team record.
The Twins embattled reliever had another miserable night.
Willians Astudillo socked a solo home run in a 2-0 victory over the Pirates
Polanco did the hitting. Nelson Cruz did the...running?
The Twins defeated the Tigers 15-6 on Monday afternoon.
Willians Astudillo is not on the playoff roster for the ALDS.
Jonathan Schoop had the honor of smacking the 300th bomba.
The Twins are 6.5 games ahead of Cleveland again.
Buxton, Gonzalez, Schoop, Cruz, Rosario and Kepler have all been dinged up recently.
Minnesota is on pace to win about 110 games.
La Tortuga's mom was part of the pregame festivities for Mother's Day.
They tied the team record with 8 homers in the second game of the day.