The Giants acquired Bresnahan and a player to be named later from the Guardians on Tuesday in exchange for Alex Cobb, Zack Meisel of The Athletic reports.
Bresnahan, who just turned 19 in June, has spent most of this season in rookie ball but recently had been promoted to Single-A Lynchburg. He's posted a promising 2.70 ERA and 66:18 K:BB over 50 innings on the year.