The Twins claimed speedy outfielder off of waivers from the Toronto Blue Jays (who made room on their 40 man roster for Francisco Cordero). The Twins previous were at 40 on their roster, so someone will need to be DFAd to make room for Mastroianni. There are certainly several options.
The 26 year old went 0-2 with a sacrifice bunt in his one game with the Blue Jays in 2011. He was a 16th round pick of the Jays in 2007 out of the University of Southern Indiana, a Division II school. He had spent the 2005 season at Winthrop where he was a teammate of former Twins pitcher Kevin Slowey.
Because he has options, Mastroianni likely will play in Rochester in 2012.