Few paid much attention to the final three frames of the Cubs’ 9-4 loss to the Nationals on Saturday. But Maddon was struck by Tyler Chatwood’s work, saying: “The last couple of hitters he threw to might have been his sharpest work all year, believe it or not. And he felt the same way.” Maddon cautioned that it was a “first step,” so it’s not as if Chatwood is about to bump off Jon Lester. But if the Cubs expand to a six-man rotation in September and Yu Darvish can’t answer the call, Chatwood could reclaim a spot.