With relievers Mitchell Boggs and Fernando Salas off to the World Baseball Classic for anywhere from a week to nearly three weeks, the Cardinals’ bullpen will take on a different look. Boggs will have the eighth inning waiting for him when he comes back. Salas, who spent some time in the minors last season, has taken a calculated risk in going to the WBC although he has on his side those club-leading 24 saves he amassed in 2011 and his efficient pitching this spring in which he has allowed just one hit, a home run, in 10 at-bats. Manager Mike Matheny said he would be paying attention to Salas’ performances for Team Mexico because the pitcher probably will be facing as good a competition there as he would in spring training. But Salas’ temporary absence, and to a lesser extent that of Boggs, has opened the door for righthander Eduardo Sanchez, who has had some success with the Cardinals in each of the last two seasons, and also for Trevor Rosenthal, who appears more fowl (reliever) than fish (starter). Sanchez said he could appreciate the extra chances he will get. “Absolutely,” he said. “With Boggs and Salas gone, that’s two more innings.”