Thome agreed to terms with the Twins on a one-year, $1.5 million contract last week. But he needed to take a physical and the Twins needed to make a roster move before making the signing official.
It turns out the Twins had the roster move made for them when the Oakland Athletics claimed Steve Tolleson off waivers on Monday.
Thome is expected to spend most of his time with the Twins as a pinch hitter. Manager Ron Gardenhire says Thome will also see some time at DH and could spell Justin Morneau at first base occasionally this season.
The Twins report to spring training in Fort Myers, Fla., on Feb. 26.