ST. LOUIS -- The Cardinals added two top prospects to their roster to protect them from the Rule 5 Draft this year, with No. 4-ranked prospect Ivan Herrera -- whom many in the organization view as the future at catcher -- added on Wednesday, and right-hander Angel Rondón -- who is the club’s No. 13 prospect, according to MLB Pipeline -- added on Thursday.

Friday is the deadline to add players who are eligible for the Rule 5 Draft to 40-man rosters, and the Cardinals still have some decisions to make with theirs now standing at 38. Right-hander Angel Rondon (the Cardinals’ No. 13 prospect, according to MLB Pipeline), catcher Julio Rodriguez (No. 15), outfielder/infielder Juan Yepez (No. 24), right-hander Roel Ramirez (No. 27) and right-hander Alvaro Seijas (No. 30) all are eligible for the Rule 5 Draft, which will take place on Dec. 10.

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Players who signed at age 18 or younger must be added to 40-man rosters within five seasons or they become eligible to be drafted by other organizations through the Rule 5 process. Players signed at 19 years or older must be protected within four seasons. This year, that means an international or high school Draft pick signed in 2016 -- assuming he was 18 or younger as of June 5 of that year -- or a college player taken in the ’17 Draft are eligible.

Clubs pay $100,000 to select a player in the Major League phase of the Rule 5 Draft. If that player doesn't stay on the MLB roster for the full season, he must be offered back to his former team for $50,000.

The Cardinals signed Herrera, 20, on July 2, 2016, for $200,000. He was earmarked to return to Double-A Springfield as its primary catcher in 2020, but with the cancellation of the Minor League season, he instead spent the summer at the Cardinals’ alternate training site in Springfield, Mo. Herrera slashed .284/.374/.405 between Class A Peoria and Class A Advanced Palm Beach in 2019 before earning an invitation to the Arizona Fall League last year and emerging as one of the top catching prospects in the Minors.

It was Herrera’s bat that caught the attention of the Cardinals’ international scouting department five years ago, and his reputation as an offensive catcher has remained throughout his time in the farm system. But his glove is starting to catch up, and he spent Spring Training and Summer Camp this year shadowing Yadier Molina to learn as much as he can. A focus of Herrera’s work has been arm strength, and the Cardinals saw improvement there this spring -- all while maintaining his offensive skills and continuing to be the baseball-savvy player the Cards saw when they signed him.

It should be noted that Herrera's addition doesn’t have anything to do with the Cardinals’ desire to re-sign Molina, who is a free agent for the first time in his career and seeking a two-year contract. As a top prospect, the Cardinals didn’t want to risk losing Herrera to another team via the Rule 5 Draft. Whether Molina returns next season or not, Herrera is still considered a part of the Cardinals’ future within the next few years.

Talks continue between Molina’s agent and the Cardinals, although the pace of those talks isn't expected to heat up in the immediate future.

Rondón, 22, was signed out of the Dominican Republic in 2016 and emerged as a steady starter as he climbed in the farm system. He spent this summer at the alternate training site after claiming the organization’s Minor League Pitcher of the Year award in 2019. Across two levels last year -- Palm Beach and Springfield -- Rondón posted a 2.93 ERA in 160 innings over 28 starts. He struck out a career high 159 batters with 59 walks while holding opponents to a .213 average.

Rondón will continue to develop as a starter until he is needed in relief. That could come as early as 2021.