The Twins have placed 2nd baseman Alexi Casilla on the 15-day disabled list with a hamstring injury.  He is likely to miss 2 to 3 weeks.  The Twins called up infielder Luke Hughes from triple-A Rochester to replace Casilla on the active roster.  The Twins are expected to use Matt Tolbert, Trevor Plouffe and Luke Hughes at 2nd base in Casilla's absence.