ST. LOUIS -- Stephen Piscotty, the Cardinals' top-ranked prospect per MLB.com's preseason list, highlights the group of 18 non-roster players who have received invitations to participate in the club's big league camp this spring.

Piscotty, a first-round pick in the 2012 First-Year Player Draft, will begin Spring Training alongside Major League players for the second straight spring. He's also one of six invitees who were ranked as Top 20 organizational prospects by MLB.com at the end of last season. Others with that distinction include Tim Cooney (10th), Carson Kelly (11th), Zack Petrick (14th), Jacob Wilson (18th) and Breyvic Valera (19th).

No one from St. Louis' 2014 Draft class earned a non-roster invite this year, though first-round picks Luke Weaver and Jake Flaherty will both participate in the STEP (Spring Training Early Program) initiative that the Cardinals host for select organizational prospects.

The non-roster invitee list also features five players who signed Minor League contracts this offseason. The most recognizable of those names is Carlos Villanueva, whose signing was announced by the Cardinals on Wednesday. Villanueva, 31, is a nine-year veteran who offers the club flexibility and insurance for both the rotation and bullpen.

Video: [email protected]: Villanueva shuts down Reds over 2 1/3 frames

Catcher Alberto Rosario, infielder Scott Moore, right-hander Miguel Socolovich and right-hander Marcus Hatley signed Minor League deals with the organization before the end of the last calendar year.

With these 18 participants added to the 39 who are automatic invites by way of being on the team's 40-man roster, the Cardinals now have 57 players slated to participate in big league camp, which begins on Feb. 20. The organization has preferred to keep that number at or just below 60 in recent years so as not to crowd the early workouts.

The full list of 18 non-roster invitees is as follows:

Pitchers: Cooney, John Gast, Mitch Harris, Hatley, Dean Kiekhefer, Mike Mayers, Petrick, Socolovich, Villanueva

Catchers: Steve Bean, Kelly, Rosario, Travis Tartamella

Infielders: Moore, Valera, Wilson

Outfielders: Rafael Ortega, Piscotty

The Cardinals set Feb. 19 as their report date for all pitchers and catchers participating in Major League camp. The organization's first full-squad workout will take place on Feb. 25, eight days before the team begins Grapefruit League Play.