WASHINGTON -- After gutting the bullpen last winter and bringing in several new faces, general manager Jim Hendry watched his relief corps get off to an awful start in 2009.

The Cubs' bullpen ranked 15th out of 16 National League teams on May 12, new closer Kevin Gregg was getting booed at Wrigley Field and manager Lou Piniella was getting antsy.

But things began to improve when Piniella began using Angel Guzman in more late-inning pressure situations in mid-May, and replaced demoted left-hander Neal Cotts in favor of starter Sean Marshall in early June.

The revamped pen entered Saturday's game ranked sixth in the NL with a 3.79 ERA, an improvement over last year's 4.10, which ranked eighth.

"I thought a while back that we could put together a workable bullpen that would function and help us win games," Piniella said. "And it has."

Piniella said his only concern is the lack of innings from his starters in the first three games of the second half. Rich Harden (six innings), Carlos Zambrano (five) and Randy Wells (five) forced Piniella to use his bullpen in 11 out of the 27 innings this weekend in Washington.

"We can get by with it now because everyone's fresh from three days off, but we're going to have to get a few more innings from our starters," Piniella said. "But we have some nice arms. I like our bullpen. We have a nice combination to go to."

Piniella relies on five relievers -- Gregg, Carlos Marmol, Aaron Heilman, Guzman and Marshall. From June 1 through Saturday's game, Gregg, Heilman, Guzman and Marshall have combined for a combined 2.39 ERA. Marmol struggled in June and had control issues again Saturday, but has a 1.13 ERA in July.

"The pen has been really good the last month," Hendry said. "Kevin has lost a couple of tough ones but bounced back with a lot of resiliency, and he's throwing the ball a lot better.

"Marmol has been better the last few weeks, and Heilman for the last month or so. Guzman has been good, and Marshall has been terrific. The pen, all of sudden, has been stable."