On Tuesday he committed an error in the first inning, mishandling the ball when Tampa Bay's Corey Dickerson singled to right, though he did catch Casey Gillaspie's fly leading off the third.
Mancini, who has been a first baseman, needs to learn another position in order to find a regular Major League job. Chris Davis, who re-signed for seven years in January 2016, has first base locked down, and Mark Trumbo, who re-upped for three years this past January, is slated to be the regular designated hitter.
Manager Buck Showalter had Brady Anderson, vice president of baseball operations, and first-base coach Wayne Kirby, who works with outfielders, tutor Mancini.