Poll No. 1: What has been the biggest key to the Cubs’ best-in-baseball start?

Upshot: Kyle Hendricks, who threw a shutout on Opening Day, has stepped into Jon Lester’s topof-the-rotation shoes and looked extremely comfortable. Lester himself has been far better than anyone could have expected. And how welcome has Yu Darvish’s mini-roll been, with victories in three straight starts for the first time since 2014? Heading into the season, the rotation, especially after Jose Quintana’s freak injury, looked like a potential weakness. Instead, it’s the backbone.