Kyle Gibson could be traded
Kyle Gibson was brought in on a one-year contract with a club option for the 2025 season. Gibson has been quite effective as a middle-of-the-rotation starter recording a 3.97 ERA in his first 20 starts this season. His ability to go deeper into games and notch quality starts is extremely valuable in an era of load management. By consistently giving the Cardinals a chance to win with each outing, he's the second most valuable starting pitcher on the roster by quite a wide margin.
With the market of starting pitching looking extremely thin, especially if teams like the Texas Rangers don't sell at the deadline, Gibson could be one of the better arms available for teams looking for innings. If the Cardinals do decide to sell, Gibson would certainly bring back quite an impressive return for a rental. Given the package the Rays got for Zach Eflin, and what other sellers will certainly get for their arms, it could be very favorable for the Cardinals.
Ryan Helsley could be traded
Even if the Cardinals don't fully sell at the deadline, Ryan Helsley could find himself on the move. The market for relief pitchers looks incredibly thin, and considering the Angels got for rental closer Carlos Estevez, the Cardinals could get an absolute haul for their All-Star closer. Unlike Estevez, Ryan Helsley comes with an extra year of control and has a much stronger track record.
The Phillies gave up their 7th and 12th-ranked prospects for half a season of Estevez, so imagine what the Cardinals could get from the Dodgers or Orioles for an extra season of Ryan Helsley. It's unlikely St. Louis would extend Helsley past the 2025 season, considering the massive contracts top closers have been getting, and with the volatility of relievers, it may be best to sell high on one of the best closers in baseball. It may not be popular, but a Helsley trade would not be surprising at all.