Every player has their triumphs and struggles, for whatever reason(s). Lance can really be up-and-down and the most noticeable factor is MM vs no MM. 2015 Home 1.86 ERA (10 starts) Away 4.60 ERA (12 starts) 2016 Home 2.40 ERA (10 starts) Away 5.57 ERA (4 starts) 2017 Home 2.77 ERA (2 starts) Away 10.39 ERA (1 start) Players usually perform better at home, but Lance's numbers are alarming. Fixable?
Like you said, every pitcher has some degree of home/road splits. It's just developing pitchability. Hopefully working with McCann will help Lance develop a better game plan than "hopefully my fastball's missing bats and the curve is on point". He's already made some developmental strides early. He's got some quick outs early in the first two starts that allowed him to go longer. He needs to develop a better weak contact strategy in tight situations. Lance is awesome but he's still more thrower than pitcher at this point.
Much like Correa, several still forget how young he is... and how much further he has to develop to be in-line with most guys starting out year 3. He's definitely more of a pitcher than several predicted he would be at any point in his MLB career.... but agreed he's got to refine certain situational aspects.