Change #6 - Sit Tommy Edman against RH pitching, start Paul DeJong
This may not be a move I would stick with long term, but for the time being, Paul DeJong should be playing every day against right-handed pitching, while Tommy Edman moves to the bench.
DeJong has done nothing but rake since coming off the injured list this year, and has been one of the most productive Cardinals during that time. DeJong is now tied with Nolan Gorman for WAR on the season (0.7) and ranks ahead of both Brendan Donovan and Tommy Edman (both are at 0.4). DeJong has done this in about a third of the plate appearances and innings played that the other three have had.
Checkout DeJong and Edman's splits against RH and LH pitching, respectively.
vs. RH: .387/.441/.774 with 3 HR and 6 RBI (231 sOPS+)
vs. LH: .222/.300/.222 with 0 HR and 0 RBI (46 sOPS+)
vs. RH: .177/.258/.304 with 2 HR and 9 RBI (57 sOPS+)
vs. LH: .400/.455/.767 with 3 HR and 5 RBI (224 sOPS+)
This is the ultimate example of an elite platoon opportunity, and the Cardinals need to take advantage of that at shortstop for as long as it lasts. Late in games, the Cardinals can counter with the other half of the platoon as a pinch-hit option as needed, making it a deadly combo for opposing teams to face.
DeJong being a prominent bat in their lineup against right-handed pitching and Edman doing the same against left-handed pitching strengthens the lineup in a big way and really helps make up for a slumping Nolan Arenado. If he can get things back on track soon, this lineup is scary.