The Cardinals fill out their rotation as well
Yes, St. Louis needs top end pitching to matchup with some of the best teams in the National League, but they also desperately need other arms as well who can help save the bullpen form the extreme pressure they’ve been under to this point.
I would be extremely surprised if this is the biggest move St. Louis makes, but it is needed in order to get this club into October baseball. Some potential names that could fit this mold for St. Louis includes Jose Quintana, Madison Bumgarner, Merrill Kelly, and Zach Plesac.
Quintana, coming over from Pittsburgh, would be a quality innings eater for the club, which will be critical for the club making the playoffs. Even just 5 quality innings from start to start would allow St. Louis to let their bullpen breathe, and could improve the production of the enitre pitching staff.
If the Cardinals do grab Soto, they may look to make two of these kind of pitching moves to find more innings, and even could if they acquire a front line starter like Montas. The Cardinals really only have three reliable starters healthy in Adam Wainwright, Miles Mikolas, and Andre Pallante, so grabbing multiple arms would go a long way.