The Twins placed catcher Joe Mauer on the 15-day disabled list with leg weakness and called up catcher Steve Holm from triple-A Rochester to replace him on the active roster.  Mauer will fly to Baltimore to see a specialist before returning to the Twin Cities to begin rehab.  Mauer was placed on the 15-day disabled list retroactive to April 13.  Manager Ron Gardenhire feels Mauer has been compensating for his knee injury and it has caused bi-lateral leg weakness and hip soreness.  Drew Butera will assume the regular catching responsibilities for the Twins.