The Cardinals on Thursday made three roster moves in advance of Friday's deadline to protect players from being plucked in the Rule 5 Draft.
The Cards purchased the contracts of shortstop Aledmys Diaz and left-hander Dean Kiekhefer from Triple-A Memphis and added outfielder Charlie Tilson from Double-A Springfield. With those moves, the Cardinals have 36 players on their 40-man roster.
Diaz, halfway through a four-year, $8 million deal with St. Louis, was taken off the Cards' 40-man roster earlier this year. The 25-year-old hit .333/.404/.574 in his final 45 games last season, putting him in position to contend for a backup infielder role next year.
Kiekhefer went 2-1 with a 2.41 ERA in 50 games for Memphis last season, walking only seven batters in 59 2/3 innings. The 26-year-old, currently playing in the Arizona Fall League, could find a role as a lefty reliever for the Cards next year.
Tilson, 22, hit .295/.351/.388 with 46 stolen bases while primarily playing center field for Springfield last season. A second-round Draft pick in 2011, Tilson is ranked as the Cards' seventh-best prospect, according to MLB Pipeline.
Adding Diaz, Kiekhefer and Tilson to the roster ensures they cannot be selected in December's Rule 5 Draft. Assuming the Cardinals don't add any more prospects to their roster before Friday's 10:59 p.m. CT deadline, they left several intriguing prospects exposed to other teams in the annual draft.
That group of available prospects includes right-hander Luis Perdomo, their No. 11 prospect. Perdomo, who represented the Cards at the All-Star Futures Game, posted a 3.98 ERA over 23 appearances (22 starts) at two Class A levels last season. Given his distance from the Majors, it's unlikely -- but not impossible -- that another club would draft Perdomo and attempt to carry him on its 40-man roster all season.
Also left off the Cards' roster is infielder Jacob Wilson. He is a versatile defender capable of playing both second and third base, but he hit just .230/.302/.407 while playing at Double-A and Triple-A last season.
Third baseman Patrick Wisdom, the Cardinals' No. 12 prospect, is another potential Rule 5 Draft candidate. Wisdom spent his second straight season in Double-A this year, batting .237/.294/.406 in 114 games. Wisdom was also sent to the Arizona Fall League this year.
Adam Berry is a reporter for MLB.com. Follow him on Twitter at @adamdberry. This story was not subject to the approval of Major League Baseball or its clubs.