LOS ANGELES -- The Los Angeles Dodgers' bullpen is a baker's dozen strong now and looking to rise to the occasion at just the right time.

A team strength all season, the relief corps started to show some vulnerability of late, but the fortuitously-timed expansion of rosters in September has the group starting to feel fresh again at 13 members.

On Tuesday night it gave four more strong innings to the cause in a 5-2 victory over the Arizona Diamondbacks, after starting the day with 488 innings on the season, second most in the National League. The victory kept the Dodgers four games ahead of the San Francisco Giants in the NL West.

A heavy workload for the bullpen means a lack of lengthy starts from the rotation. The Dodgers have done well with those relief innings, though, as their 3.39 ERA heading into play Tuesday was among the best in the NL.

Kenley Jansen completed four shutout relief innings by the Dodgers' bullpen with his 42nd save of the season. Kirby Lee/USA TODAY Sports

In addition, their 1.14 WHIP led the NL, and their 3.01 strikeout-to-walk ratio was a tick behind the NL-leading Washington Nationals.

"We added Joe Blanton and Louis Coleman, and we had that great stuff [before that]," said Kenley Jansen, who closed out Tuesday's victory with his 42nd save in the 400th appearance of his career. "We just have to find that consistency, and I feel that this year we have found that consistency."

But even as the impressive numbers continued to roll in, manager Dave Roberts always was leery about the moves he had been making out of necessity. It was not that long ago when a six-inning start seemed like a luxury, as five-and four-inning outings from the starters became the norm.

"Yes, you look at the numbers, our pen has been used a lot we all know that," Roberts said. "There were some nights when we had maybe nine guys in the pen. Right now we're looking forward to Clayton [Kershaw] getting back and with what Rich [Hill] has given us, Kenta [Maeda], I think we're trending the right way."

When Kershaw was one of the few Dodgers leading the charge in the early going, he was giving the Dodgers length and at least giving the bullpen a break every fifth day. When Kershaw went down on June 26, it was no surprise that the bullpen was being asked to red-line the engine. Going full-throttle every night is brutal on engine wear.

With Kershaw returning Friday and Hill set to make his third Dodgers start a day later, Roberts says he hopes to get his relievers a double-dose of rest and relaxation to go along with the group's increased numbers. Improved length from the starters had already started in advance of Kershaw's return as Maeda, Hill and rookie Jose De Leon all went six innings or more recently.

"Yeah, I think our bullpen is in a pretty good situation," Roberts said. "Obviously when you've got a bunch more arms out there it helps, but the start that Kenta gave up [Monday] was certainly big. But it's a lot easier to mix and match guys and kind of be really mindful of their usage."

Making the bullpen's run even more incredible is that Jansen is the closer and the set roles seem to stop there. Blanton has been the closest thing the team has had to a setup man, and has certainly been the group's steadiest arm outside of Jansen, but others have set up victories as well.

Blanton set up Tuesday's victory and could give Roberts some stability in the role, but the manager was not about to commit just yet.

"Joe's been great for us, he really has against right-handers and left-handers," Roberts said. "He's done some long relief early, he's pitched in the fifth, sixth, seventh, eighth. He's a guy that has really solidified our bullpen, but it's not a hard-fast rule that he's going to be pitching in the eighth. I think that I used Joe in a lot of high-leverage situations and that might come in the seventh."

From the left side, what Adam Liberatore was for the Dodgers early this season with off-the-chart consistency, surprise rookie Grant Dayton has become of late. Dayton has a 1.86 ERA in 15 appearances, and has not given up an earned run over his last seven appearances (8 1/3 innings). And while J.P Howell has not been what he was in recent seasons, Julio Urias gives the club another left-handed option in relief. Urias is not one of those 13 Dodgers relievers since he has not officially been added to the bullpen just yet.

Even right-hander Pedro Baez, fired a scoreless inning Tuesday. He had struggled after recent heavy usage and returned earlier Tuesday from a short break when he was demoted but was never asked to pitch at Double-A Tulsa.

It would seem as if the Dodgers' bullpen has all it needs for crunch time ahead, except a new weapon has emerged in the season's final month. Jansen dispatched the Diamondbacks on Tuesday, throwing an effective slider to add mass confusion for hitters looking for a cut-fastball.

Turns out, it is no surprise Jansen is showing the pitch now with the stretch drive coming and a potential playoff berth ahead.

"Yeah, definitely," Jansen said. "To me it's always going to help you because I feel like hitters, no matter what -- and you can ask any hitters in here, too -- if they're going to face me, I think we all know they have to be geared up waiting for the fastball. It definitely is going to be a great out pitch for me to use."

If the Dodgers can play it just right, they can have a rested and unpredictable bullpen the rest of the way.

"It's awesome man," Jansen said about the 13-man bullpen, that could grow to as many as 15 in the coming days. "That helps a lot. When you have stuff like that, especially with our bullpen getting beat up, that will prevent people from getting hurt. It definitely helps."