Manager Joe Girardi has not yet announced the Yankees’ Opening Day lineup against the Red Sox, and the biggest question is: Who will catch CC Sabathia? Last season Girardi paired the staff ace with Chris Stewart 18 times and Russell Martin 11. However, Martin caught Sabathia’s last four games (including three in the postseason) and last eight of nine. Martin, of course, is now with the Pirates, and Francisco Cervelli is back from a season spent at Triple-A to join Stewart. Girardi gushed about Cervelli’s defensive improvement — especially his throwing — during spring training and could start him today. Cervelli is potentially a better hitter than Stewart, but Girardi stresses defense from the position. Sabathia had a 3.16 ERA throwing to Stewart; 3.75 with Martin a year ago. * When Rafael Soriano left the Yankees via free agency, the team slept well knowing Mariano Rivera was back to close. And they believed David Robertson could handle the eighth inning better than a year ago, when some thought a rib cage injury bothered him throughout the season.