Lester seems to be recreating himself as a pitcher late in his career. I know it's just 3 starts in a weird season but he's getting outs without throwing a ton of pitches or having to strike guys out. I have been skeptical of Happ being a long term player on this team but Ross keeps putting him out there and he is producing so far.
What is crazy right now is the struggles of Bryant and Rizzo at the top of the order which are 2 of the best hitters on the team yet they are still scoring a lot of runs most nights.
The Cubs signed Lester with the belief that he would be able to age gracefully. 2015-16, they got the kind of ace-level performance they wanted. I think it's becoming clear that his relative struggles over the last few years were part of the process of adjusting to his new reality. He can't beat guys with pure stuff anymore, and it took awhile to figure out how to pitch well without that. Now he seems to have figured it out.
I'm definitely a believer in Happ, or at least a believer in his bat. His defense in CF is passable, but hopefully that improves as he gets more experience out there. Offensively, the tools have always been there, but now he's put it all together. His command on the strike zone is crazy. He's chasing out of the zone far less than ever before, and being more selectively aggressive in the zone. He's spitting pitcher's strikes that are tough to do much with, and attacking the strikes he can do something with. That started last season, and his contact rate on swings in the zone has skyrocketed as a result (77.9% and 70.2% in 2017 and 2018, and 82.1% last season and 84.1% so far this season).