Welington Castillo, who had been with the Triple-A Iowa team, was in Chicago in case he was needed. Cubs catcher Geovany Soto has some swelling in his right knee and the Cubs wanted a backup just in case he was unavailable for an extended period of time.
Because Castillo was with the Cubs until Aug. 22, he is not eligible to be added to the team until Thursday -- 10 days after being sent down. However, if Soto had to go on the disabled list, the Cubs could activate Castillo immediately.
The Iowa team has a half-game lead in the Pacific Coast League Northern Division and there isn't a need for more players other than another catcher on the big league team.
The Cubs were expected to add six or seven players once the Iowa team is finished in the playoffs. Among the candidates are pitchers Justin Berg, Jeff Stevens, Mitch Atkins, and Jeff Samardzija, and outfielders Sam Fuld and Brad Snyder.
One thing the Cubs want to look at for 2011 is whether Tyler Colvin can handle first base. Colvin, who leads all Major League rookies with 19 homers and has only played in the outfield, has been taking grounders at first.
"You've got to find out about the kids, one way or the other," Cubs manager Mike Quade said. "You wouldn't do it against a contender. There are still 30 or 20-something games left, and you'd like to find out."
Colvin hasn't played first since his sophomore year of college -- and that was part-time.
"I want him to be able to relax and do it, and if I don't have to, for whatever other reasons, we won't," said Quade, who will rely on his coaches' feedback as to whether Colvin is ready.