The Houston Astros made two bold statements before the trade deadline Tuesday, the biggest of which was acquiring Pedro Astacio from Colorado for pitcher Scott Elarton, a player to be named later and cash.

In a separate deal, the Astros strengthened their bullpen by adding closer Mike Williams from Pittsburgh in exchange for right-hander Tony McKnight.

Pedro Astacio pitched his last game for the Rockies last Friday night.(AP)

The moves should allow Houston to keep pace with the Chicago Cubs in the NL Central, who have added first baseman Fred McGriff, outfielder Michael Tucker and reliever Dave Weathers.

"He's just a better pitcher than some of the guys we have in the rotation," Astros manager Larry Dierker said of Astacio. "He's been a workhorse. He hasn't always been effective.

"He's not in a class with (Greg) Maddux, (Pedro) Martinez or Randy Johnson, but he's just a notch below. I know he has a losing record this year but that doesn't bother me that much."

Astacio is just 6-13 with a 5.49 ERA this season, though scouts like his stuff and think he will be better served once he leaves Coors Field. He's lost eight of his past nine decisions and has just one win since June 3.

Still, he's Colorado's all-time leader in wins (53), innings pitched (827 1/3), starts (129) and strikeouts (740).

"Astacio is a guy that obviously is not having a great year," Astros general manager Gerry Hunsicker said. "But take him away from Coors Field and he's pitched better away from home.

"He's a guy with great intensity and great fire. He's a guy capable of pitching some big games and a guy I think has a chance to come up big for us down the stretch."

Like Astacio, Elarton may be able to benefit from a change of scenery.

After going 17-7 with a 4.81 ERA last season, Elarton has been awful this year. Currently on the disabled list with biceps tendinitis, he's 4-8 with a 7.14 ERA in 20 starts. Opponents are batting .290 against him.

"Last season was great for me," Elarton said. "Unfortunately, this year has not been good at all. I wouldn't be standing here right now if I'd had a good season. It's a business, and you've got to treat it that way."

As for Williams, Boston and Los Angeles were having conversations with Pittsburgh about him, a source within the Pirates' organization told SportsLine.com, through Tuesday morning, when new Pittsburgh general manager Dave Littlefield finally pulled the trigger on the Houston deal.

"Williams is a guy that seems not to make sense for us," Hunsicker said. "We've got a good bullpen and a good closer. But a lot of things happen down the stretch and this as much to fortify our bullpen as anything."

McKnight, the Astros' first-round pick in 1995, appeared in just three games for Houston this year, going 1-0 with a 4.00 ERA.

The Associated Press contributed to this report.