1. Front-of-the-rotation starter
It's time. The Cardinals have to find a player worthy of pitching on Opening Day, not just because of the history that player has with the organization or because he's their "best option", but a guy that can go toe to toe with the best in the game.
I don't care how they choose to acquire said player. They may have to offer a franchise record contract in free agency to get it done. They may have to part with multiple young bats that they really like in order to bring that player in. Whatever it takes, the Cardinals need that ace, and they need him by Opening Day.
The list of players that can fit this mold is pretty thin. In free agency, Aaron Nola or Japanese sensation Yoshinobu Yamamoto are the two starters at the top of the market that St. Louis may find themselves going for. Names like Blake Snell or Marcs Stroman would fit the bill as well but at a smaller cost (or potentially years on the deal).
In the trade market, Dylan Cease appears to be the offseason's biggest trade chip on the market, so St. Louis will have to win a bidding war against other teams and offer the strongest package. They could turn their attention to Seattle and pursue Logan Gilbert, although he's more of a number two starter, or go after the Rays' Tyler Glasnow, who has injury concerns.
Whatever way the Cardinals choose to go in the "front-line pitching market", they will incur risk. It could be the risk of handing out a 5+ year mega deal to a starting pitcher, hoping they perform to the numbers they are getting paid. It could be hoping that the strong package they give up in a deal is worth the starter they get in return.
No matter what, they have to pay the price to get an ace. They cannot go into Spring Training next year and say, "Well, the market was different than we thought it would be and we were not comfortable making those deals". That won't fly this time.