The final month offers more opportunity for players to show they belong. And shortly after the season, the front office will meet and decide who will be part of the plans for 2013.
The organization has to be able to sit back after the season to accurately evaluate, rather than make hasty decisions.
"Right now, if you are going to evaluate players, I don't think that's a nice way to do it," Guillen said. "If you have a meeting about players right now, after the way we've played all year long, with all the expectations ... you're not going to make the right decision, because you'll be making it with your heart and not with your brains. Because you're going to hate everyone."
Right now, the club is a mixture of veterans and younger players. John Buck is splitting the catching duties with Rob Brantly, a 23-year-old just now getting a taste of the big leagues. The starting rotation has two rookies -- Nathan Eovaldi and Jacob Turner.
"We've got to be patient and we've got to be very realistic about what kind of ballclub we're going to have in the future," Guillen said.
Eovaldi, 22, has impressive stuff. His fastball regularly reaches the upper 90s. But he struggles with command, which has led to trouble and short outings. And Turner, 21, has just two starts since being called up from Triple-A New Orleans.
Guillen noted that both still have to earn a spot in the 2013 rotation.
"We're not saying we're going with them next season," the manager said. "We're looking at them this season to see if they can help us next season. What I'm looking for is strikes.
"They're going to compete for a job next year. This year, we want them to get their feet wet."