The Cardinals added three players to their 40-man roster on Friday -- including a surging prospect raking in the Arizona Fall League -- in order to protect each from being selected in the upcoming Rule 5 Draft. At the same time, the club left exposed a first baseman with prodigious power and a former top Draft pick, among others, leaving them vulnerable to the possibility of being selected by another organization.

Third baseman/outfielder Brendan Donovan (the club’s No. 17 prospect and an Arizona Fall League All-Star), was added to the 40-man roster ahead of Friday’s 5 p.m. CT deadline, along with right-handers Jake Walsh and Freddy Pacheco.

Among those not added: shortstop Delvin Pérez (No. 12 prospect and 2016 first-round pick), first baseman Luken Baker (No. 13 prospect), outfielder Jhon Torres (No. 19), catcher Julio E. Rodriguez (No. 20) and infielder Kramer Robertson, who, along with Donovan, was on the Cards' small taxi squad for the 2021 postseason.

Players selected in the Rule 5 Draft, currently scheduled for Dec. 9, are assigned directly to the drafting club's 26-man roster and must be placed on outright waivers in order to be removed from the 26-man roster in the subsequent season. Should the player clear waivers, he must be offered back to his previous team for $50,000 and can be outrighted to the Minors only if his original club does not wish to re-acquire him. Players signed at age 18 or younger need to be added to their club's 40-man roster within five seasons or they become eligible for the Rule 5 Draft. Players who signed at age 19 or older need to be protected within four seasons.

Another notable name among the group not added to the 40-man roster was outfielder Nick Plummer, the club’s top Draft pick in 2015 and the Cards' No. 10 prospect come the end of the 2021 regular season. That’s because Plummer was instead granted free agency on Nov. 7, a surprising move given that he had a torrid season (a .415 on-base percentage alongside a .894 OPS between Double-A Springfield and Triple-A Memphis). Plummer was also included on the taxi squad for the postseason, but the emergence of left-handed-hitting Lars Nootbaar and 70th overall 2020 Draft pick Alec Burleson (No. 11 prospect) likely squeezed Plummer out of having a quick path to the Majors.

But perhaps most surprising about the slate of players left unprotected are Pérez and Baker. The former was a highly touted prospect but struggled at every point of his Minor League career before finding some modest footing in 2021, with a .265/.322/.339 slash line at Double-A Springfield. However, the 22-year-old went unprotected ahead of last year’s Rule 5 Draft, too, and was not selected then; the Cards could be banking on other teams also not believing Pérez is Major League ready. On the flip side, a club could be tantalized by his raw skills -- defense and speed chief among them -- and look to replenish its shortstop depth.

Baker, meanwhile, blasted off 26 home runs this season at Springfield and earned a late-season callup to Memphis. Like Plummer, the slugger’s immediate path to the big leagues may have been blocked by the emergence of Juan Yepez, who was added to the 40-man roster in October and stands to serve as either a designated hitter (if one is added to the NL) or a backup first baseman to Paul Goldschmidt in 2022. And like Pérez, Baker may be seen as a little too raw to be given a chance on a Major League roster next season.

Awarded for a sensational season, however, was Donovan. The club’s seventh-round pick from the 2018 Draft put up a .304/.399/.455 slash line after he started the year at High-A Peoria and ended it at Memphis. The 24-year-old has increased his versatility as well by learning to play outfield, and is among a handful of young Cards putting on a show in Arizona this fall.

Walsh, 26, put up a 2.86 ERA in 17 relief appearances for Springfield and Memphis this season, and featured a gaudy 13.9 strikeouts-per-nine innings. Pacheco, 23, recorded a 3.67 ERA in 41 games from High-A all the way to Triple-A, notching 11 saves for Peoria and Springfield along with an astronomical 15.8 strikeouts-per-nine, and he is now pitching in the Venezuelan Winter League.