Happ went four innings in his debut in Detroit, and got a no-decision.
The Twins blew a 6-0 lead and lost 8-6 to Seattle on Sunday as Alex Colomé blew his second save, allowing a three-run home run to Kyle Seager in the ninth inning.
Twins starters are 5-0 this season with a 2.44 ERA.
Center fielder Byron Buxton leads the majors in slugging percentage at 1.185, with Boston's J.D. Martinez right behind at 1.083. Martinez hit three homers yesterday in a victory over Baltimore.
Third baseman Josh Donaldson (right hamstring strain) played five defensive innings at the alternate training site in St. Paul yesterday afternoon in an intrasquad game, and had six at-bats with no medical issues.
Baldelli said the Twins would hold off on Donaldson's return until the weather improved
Today is the 11th anniversary of the Twins' first game at Target Field, one where they beat the Red Sox 5-2.