4 Rule 5 candidates the Cardinals should add to the 40-man roster

OF Matt Koperniak

Matt Koperniak is one of the oldest players in the minor leagues for the Cardinals. The 26-year-old outfielder was signed as an undrafted free agent in 2020 out of Trinity College, and he has played four seasons in the minors for the Cardinals.

While his 2023 showing in Springfield -- .320/.386/.453 slash line -- was strong, he's taken it to another level this year with the Memphis Redbirds. Koperniak finished 2024 with a .309/370/.512 slash line with 20 home runs and 73 runs batted in. He also played strong defense at every outfield position.

Koperniak has experience on the international stage as well. He represented Great Britain in the 2023 World Baseball Classic, and he went 8-26 with five RBIs in spring training this year with the Cardinals.

Promoting Koperniak during the season proved difficult since Lars Nootbaar, Alec Burleson, Brendan Donovan, Victor Scott II, Michael Siani, and Jordan Walker all needed time in the grass. However, the Cardinals should look to add him to the 40-man roster this offseason if not just to protect him from other teams poaching him.

The same clogged situation may occur in 2025. Lars Nootbaar, Alec Burleson, Jordan Walker, Michael Siani, and Victor Scott II will all be fighting for roster spots. Brendan Donovan could also see some work in the outfield. That makes six major-league major-league-proven players who will be blocking Koperniak. If nothing else, adding him to the 40-man roster provides depth should injuries arise.

Matt Koperniak has hit quite well at every level of the minors. He's always been an underdog since playing for Division III Trinity College. He's a left-handed hitting outfielder who has tapped into some power recently; that's a tough combination to find elsewhere, particularly when you account for his plus defense at multiple positions in the outfield. If the Cardinals were to let Koperniak go this offseason, that may come back to haunt them down the road.

RHP Tekoah Roby

Tekoah Roby has not necessarily earned a spot on the 40-man roster due to his extensive injury history, but his pedigree and talent alone make him a perfect candidate. Roby is a former top-100 prospect in all of baseball, so the pedigree is in him somewhere still.

Roby has only thrown 50.1 innings since being traded to the Cardinals at last year's trade deadline, and his work on the mound has not exactly been inspirational in either the minors or the Arizona Fall League in 2023. He has a 5.75 ERA in the minors with the Cardinals, and he's struck out 58 batters. He's become a bit home-prone lately, but his last three games with Palm Beach to close out the 2024 season were a bit better than he was prior to that rehab stint.

What makes Roby an enticing 40-man candidate would be his age -- he just turned 23 -- and his former status as a consensus top-100 prospect in baseball. Baseball America had him #75 in their preseason rankings for 2024, and MLB Pipeline had him at #88 in 2023.

Roby features a fastball that can touch 99 at times with good command. He has a strong curveball that is a traditional 12-to-6 curve. He's recently added a slider that gets hit pretty hard, and his changeup could use some refinement. He's been fighting control issues in addition to his injuries lately, but he once boasted a walk rate that was consistently below 7%.

If Roby can stay healthy, and if he can tap back into his former self that featured 10-plus strikeouts per nine innings, the Cardinals may have a very serviceable pitcher on their hands. To give up on a former top-100 prospect this early would be malpractice. Roby, along with Quinn Mathews and Tink Hence, provides the Cardinals with ample pitching depth in the minors.