Mitch Trubisky’s preseason is over. The rookie quarterback’s four starts in place of Mike Glennon were in effect a challenging warm-up. After an open-date week to reflect on what he has done, what he has to do and how far he can go, Trubisky is eager to take the next step, which could be a significant one — or not. “I’m pretty anxious and excited about this week,” Trubisky said Wednesday. “I kind of feel like it’s a new season in a way. The last few games are what they are, but we have a great opportunity with this home game. “Taking it one game at a time, trying to be 1-0 this week. We’re only worried about the Green Bay Packers. I feel very confident and am very excited to really just start to open things up, play within myself and the offense and do my job, so the offense can succeed, and we could win more games.” It remains to be seen just how much Trubisky and the Bears’ offense can open things up in the second half with this supporting cast. The addition of wide receivers Dontrelle Inman and Markus Wheaton could provide a dimension Trubisky hasn’t had so far. But if there was a disappointment amid the excitement of Trubisky’s promotion, it’s that his mobility and elusiveness didn’t create opportunities for his receivers as theorized.