The St. Louis Cardinals are going to likely have to walk a fine line this offseason when it comes to free agency.

St. Louis took a step in the right direction in 2026, but this is still a rebuilding team that we are talking about. The 2026 season was Chaim Bloom's first one leading the charge as the Cardinals' president of baseball operations. With Bloom, the Cardinals aren't just simply waiting around for things to get better. The Cardinals traded the majority of the veterans on the roster and let the kids play. The core is in a better place right now, but this is still a young team that isn't quite at the level of contention yet.

This winter, the Cardinals will have a chance to add pieces through free agency and the trade market. But St. Louis still is likely a year away. Still, they should be looking to add when free agency opens up.

Here are six players that would improve the Cardinals.

Patrick Sandoval — Starter (Boston Red Sox)

Sandoval missed the entire 2025 season. In 2026, he made 15 appearances for Boston, including 13 starts. Sandoval's numbers weren't great. He had a 5.12 ERA in 70 1/3 innings of work. But this is also a guy who had a 2.91 ERA in 27 starts a few years ago and now is further removed from the injury. Sandoval is a buy-low candidate with upside.

Casey Mize — Starter (San Diego Padres)

Mize had a 2.70 ERA in 16 starts with the Detroit Tigers in 2026 and then struggled after the trade deadline with a 7.46 ERA in 10 starts with the San Diego Padres down the stretch. That certainly didn't help his value. If he settles for a pillow deal, the Cardinals should be all over him.

Sean Newcomb — Reliever (Chicago White Sox)

Newcomb had a 3.09 ERA in 60 appearances throughout the regular season, including six starts. Newcomb tossed 90 1/3 innings throughout the regular season in his 10th big league season.

JoJo Romero — Reliever (Milwaukee Brewers)

Romero thrived in St. Louis and now is shining as a member of the Brewers after the trade deadline deal between the Cardinals and Milwaukee. Romero is four wins away from a World Series ring. Then, he'll be a free agent. The Cardinals should give him a call.

Yoan Moncada — Infielder (Los Angeles Angels)

This would be a bit bold for the Cardinals. Third base is a question mark. Thomas Saggese and Blaze Jordan are internal options. Soon enough, Jesus Baez could be as well. Moncada is someone who has been injury-prone throughout his career. When healthy, he has upside. But he has rarely been healthy. If the Cardinals don't view Saggese and Jordan as good options, maybe then Moncada would work as a buy-low option.

Martin Perez — Starter (Atlanta Braves)

Perez made 30 appearances in 2026, including 26 starts, and had a 3.04 ERA in 142 innings pitched. That type of production would be exactly what the Cardinals need.