Before yesterday, the Cardinals had just 33 players on their 40-man roster, leaving seven slots available. That is not unusual for this time of year as players often declare for free agency, like Jason Heyward and John Lackey, or are outrighted off the roster, like Pete Kozma. Those spaces are then used to sign free agents or add minor leaguers to protect them from the Rule 5 draft where players can be selected from other organizations if they are willing to carry them on the active roster the following season. The draft does not take place until next month, but the deadline to add players to the 40-man roster is today. The Cardinals added infielder Aledmys Diaz, outfielder Charlie Tilson, and left-handed reliever Dean Kiekhefer.
The three players are at different stages of their development, and adding them to the 40-man roster is not necessarily an indication that those players will play a role in the Cardinals upcoming season. The MILB.com website explains the eligibility for the Rule 5 draft:
Players who were signed when they were 19 or older and have played in professional baseball for four years are eligible, as are players who were signed at 18 and have played in pro ball for five years.
All players on a Major League Baseball team's 40-man roster, regardless of other eligibility factors, are "protected" and ineligible for the Rule 5 Draft.
DIaz, who signed from Cuba in 2014 played professionally in his native country for several years. He was actually on the 40-man roster earlier this season, but the team risked losing him by passing him through waivers. No team claimed him, and the Cardinals retained his rights. Diaz started the year slowly, but between Double-A and Triple-A, he ended the season hitting a solid .278/.339/.445 and might have a shot at a utility spot next year depending on the rest of the Cardinals moves this offseason.
Kiekhefer was the Cardinals 32nd round pick in the 2010 draft out of the University of Louisville. He is lefty reliever who could assume some sort of LOOGY role in the future, perhaps as early as this season. He is not a big strikeout guy with 37 strikeouts in 59.2 innings pitched last season in Memphis, but he walked just seven of the 248 batters he faced, 2.8% walk rate. He could be a solid asset for the big league club if he can keep his walk rate down without giving up damage to big league hitters.
Tilson is probably the furthest from the majors of the three players added to the roster. The Cardinals drafted him out of high school back in 2011, and he has taken a slow but steady ascent up to Double-A last season. He does not have a lot of pop in his bat, but he gets on base and can steal once he is aboard. He is the prototypical old-school leadoff hitter who can handle center field. He might not get to the majors in 2016, but the Cardinals felt it safer to put him on the 40-man roster and not risk losing him in next month's Rule 5 draft.
All three players have been playing in the Arizona Fall League, another indication that the Cardinals feel the players have a future at the major league level. With these three additions, the Cardinals 40-man roster is up to 36 players, although there are a few players who could either be non-tendered (Steve Cishek) or potentially traded (Peter Bourjos) which would free up even more space for the Cardinals to bring in players currently outside the organization. Lance Lynn's eventual spot on the 60-day disabled list will also free up a spot.
As it stands right now, the Cardinals 40-man roster is as follows: