Twins' catcher Joe Mauer is scheduled to be activated from the disabled list Friday and start against the San Diego Padres at catcher.  Mauer completed his rehab assignment at Class A Fort Myers Wednesday after facing live pitching against teammate Joe Nathan.  Mauer has been out of the lineup since April 12 because of leg weakness.  Shortstop/2nd baseman Tsuyoshi Nishioka was activated from the 60-day disabled list Wednesday night before the game but did not play.  Nishioka has played just 6 games for the Twins this season before suffering a broken leg.  Nishioka is expected to be the regular shortstop for the Twins starting today against Chicago.  Alexi Casilla will likely take over as the regular 2nd baseman.