2. The Milwaukee Brewers
Starting pitching has been the Milwaukee Brewers' bread and butter for a while, and former Cy Young award winner Corbin Burnes has been leading the staff for years. But Burnes is having an uncharacteristically down year with an ERA of 4.10. He is still striking out nearly one batter per inning and on pace to throw close to 200 innings, he just hasn't been as sharp as his usual sub-3 ERA performances. This may have something to do with the team penny-pinching him in arbitration negotiations before the season started, or maybe he has just fallen down to Earth. In any case, I'm sure Milwaukee would love to have the old Burnes back.
The Brew Crew has also been without their co-ace Brandon Woodruff, who has been sidelined with a shoulder injury nearly all year. They are getting good value out of southpaw Wade Miley when he's healthy (2.91) but Colin Rea (4.57) and Freddy Peralta (4.65) have not been spectacular. The team is also seemingly riding with a six-man rotation right now, as Julio Teheran and Adrian Houser are also getting regular starts. In any case, the starting pitching is usually much better up in Milwaukee but it is floating in the middle of the pack at 12th in combined ERA right now.