The Twins on Thursday picked up outfielder Darin Mastroianni on waivers from Toronto. To make room for him on the 40-man roster they designated pitcher Esmerling Vasquez for assignment.
Mastroianni, who is 26 and appears to have at least one option left, isn't real likely to make the 25-man roster, barring injuries to the center fielders ahead of him (Denard Span and Ben Revere). Like them, he's a speedy guy without much power; he's shown excellent stolen base rates in the minors and, as he's reached the upper levels of the Toronto system, has drawn walks. He figures to give Rochester a legitimate center fielder, which will make it easier for Gene Glynn to focus Joe Benson on mastering an outfield corner.
Vasquez winds up never having thrown a pitch for the Twins; they picked him up on the next-to-last day of the season in 2011 and cut him less than two weeks before pitchers and catchers report. He is arguably better than Jeff Gray, who remains on the 40-man roster, but if I was right in my attempt to figure out how many options the pitchers have, Gray offers a bit more roster flexibility. It's possible Vasquez will clear waivers and remain in the Twins system.
Either way, this is definitely tinkering at the edges of the roster, with a greater impact on the Triple A team than on the major league squad.