"These kids have really responded to this environment," general manager Ed Wade said of his rookies. "In the heat of the battle, playing teams that are in it to win it, these kids have handled themselves very, very well."
Houston has routinely started four rookies since dealing Berkman to the Yankees: Chris Johnson at third base, Jason Castro at catcher, shortstop Angel Sanchez and first baseman Brett Wallace.
Johnson, who leads the team with a .319 average, has been with the team in September a couple of times before for short periods. He credits some of his success this season to knowing he was with the team to stay after being called up in June.
"I think it's just that we're all having fun," he said. "We're playing relaxed. We know we're not in the race. So really we're just going out there with nothing to lose. Trying to have fun and trying to win as a group."
Two of the team's only remaining stars, Hunter Pence and Carlos Lee, have also been better of late. Lee was second in the majors with 25 RBIs in August and Pence's 45 RBIs since the break are the most in the National League.
Pence said the foundation of young players should help the Astros be an improved team next season.
"We have a lot of confidence," he said. "We have a lot of guys who are great ball players and we have more talent than people know about. But we know and that's all that really matters. It doesn't matter what anyone knows or says it's what we go out and do."
Los Angeles Dodgers manager Joe Torre, whose team split a four-game series with Houston last week, likes what the Astros have done with the team.
"It's a lot tougher to do nowadays because with the icons or favorite players, you know there's going to be criticism when those guys leave," he said. "So it's not an easy decision to make to cut the ties. You still love them and all that stuff, but with them you haven't gotten better. So you have to see how you can get better.
"I think it's taken a lot of courage for them to do this. I admire what they're doing. It's something that I think has to be done."
Over the last month, the Astros staff has gone 19-9 and has a major league-low 2.48 ERA. The top four in the rotation should remain in place for next year with Brett Myers leading the group.
"The starting rotation is fresh, young arms," Wade said. "Myers is the sage veteran at 30. So that's a good starting point to have those elements in place."
Myers has been the most consistent pitcher on the team in his first year with the Astros and became just the eighth pitcher in 90 years to throw six or more innings in 30 consecutive starts. He's 12-7 this season, his best record since posting an identical mark in 2006 for Philadelphia.
Lefty Wandy Rodriguez shook off a tough start to the season to win eight of his last 10 decisions and lower his ERA to 3.77. J.A. Happ, who was acquired in the trade for Oswalt, is 5-2 with a 3.08 ERA since arriving July 29.
Second-year player Bud Norris has impressed team officials after winning six of his last seven decisions to improve to 8-8 this season.
Wade said getting a chance to see many of his rookies for two and three months instead of just a few games in September will be invaluable.
"You get fooled by what you see in September," he said. "We certainly have a greater body of evidence that these kids can really play at this level. But we're not where we need to be. We're not pretending that we're where we need to be or want to be, but I do think that we're headed in the right direction."
Though there's still a couple of week left in the season, Johnson is already looking ahead.
"Usually at this time in the year you're not really worried about next season, you're just looking forward to the offseason but we're looking forward to next year," he said. "I think you're going to see more next year of what we've been doing this year. A lot of energy, a lot of new faces, learning as a group and winning a lot of ball games."