Not many people believed Chris Stewart would get a chance to be the starting catcher for the Yankees this season. Not even Chris Stewart. “I just assumed [Russell Martin] was coming back,” Stewart said. Even when Martin decided to sign with Pittsburgh, last year’s backup was sure the team would find a new backstop to start ahead of him. “You always do,” Stewart said. “It’s the Yankees. They always have a Plan F. But we let Russell go and it was a thin [catching] market this year.” That leaves Stewart vying for more playing time, along with Austin Romine and Francisco Cervelli. “I’m pumped,” said Stewart, whose solid work behind the plate has helped him stay in the majors despite a career OPS of just .583. “It’s a new chapter for me. I’m not used to actually going in and having a shot to be a starter. ... It shows they have confidence in the guys we have here.” Perhaps, but it also shows how much the Yankees have changed recently. As team owner Hal Steinbrenner said Friday, his goal is to get payroll under $189 million by next year to avoid the luxury tax. That means battles like the ones the Yankees are set to have to find a catcher this season may become more commonplace.