Thielbar did not make Minnesota's 30-man Opening Day roster, but is included on the three-man taxi squad that will travel with the team for the first series at the White Sox.
Thielbar has thrown all 98.2 of his major-league innings for the Twins, though none of those have come since 2015. He's since spent time in independent ball and in the minor-league systems of the Padres, Tigers and Braves. He'll likely be a frequent option on the taxi squad since he can be shuffled to and from the 40-man roster without the Twins fearing he'll be claimed by another team.