Arrieta making his claim as a No. 1

Jake Arrieta lowered his ERA to 2.77 on Monday -- a number befitting a No. 1 starter. Brian Kersey/Getty Images

CHICAGO – Is Chicago Cubs starter Jake Arrieta an ace?

The final six weeks of the season could answer that question as the Cubs attempt to play a spoiler role in the National and American Leagues. Milwaukee, Toronto, Pittsburgh and Cincinnati are just a few of the contending teams the Cubs and Arrieta will face down the stretch.

“Our schedule is going to be a tough one from here on out,” Arrieta said Monday after the Cubs lost 3-1 to the Milwaukee Brewers. “We’ll be ready for it.”

We know Arrieta will be ready. The right-hander threw another quality start against Milwaukee and gave up just five hits and two runs in 7⅓ innings pitched. He walked one hitter -- his last batter of the night -- and lowered his ERA to 2.77.

“From start to finish, it was a lot of consistency,” he said. “There’s not a break in [the Brewers' lineup]. Even with [counterpart] Yovani Gallardo. He’s one of the better hitting pitchers.”

Arrieta gets higher marks for his performance because the Brewers are indeed one of the better hitting teams in the league, though from the mound Monday, Gallardo was just as good on paper as Arrieta. The only difference is the Cubs' lineup does give an opposing pitcher a few breaks. Whatever the case, the Cubs' search for a No. 1 pitcher could start and end with Arrieta.

“It’s a position I’ve kind of been in in the past,” Arrieta said. “I relish that opportunity. It’s important for our ballclub and for every ballclub.”

Arrieta was an Opening Day starter for the Baltimore Orioles in the rugged American League East back in 2012. He knows all about expectations and is getting another chance to prove he’s the guy. Cubs president Theo Epstein is looking for top-end pitching; he might have some in his own backyard.

“Whether we develop one from an unlikely spot like Jake Arrieta or acquire someone who’s already at those heights remains to be seen,” Epstein said recently.

Can you envision Arrieta starting Game 1 -- or Game 7 -- of a postseason series? He’s starting to have that feel simply because there are days when his stuff is unhittable. And besides a blip this past week at hitter-friendly Coors Field, even on days when he's not at his best, the opposition isn’t doing much damage. After a second-inning home run by Mark Reynolds on Monday, Arrieta retired the next 13 batters. A few hard-hit balls in the seventh led to the Brewers' second run, but that’s all he would yield.

“I have to continue to work hard and do everything possible to make strides,” Arrieta said. “If I’m able to do that, I’ll be in that [ace] position for quite a while.”

The string of playoff-caliber opponents will be a big test for him at the end of a long season that has seen him move up the ladder on the starting staff. With the departures of Jeff Samardzija and Jason Hammel, the 28-year-old became the de facto No. 1 pitcher.

He hasn’t backed down.

“There’s a lot of responsibility there,” Arrieta said of being the ace. “It’s a position I’m confident to be in.”

But are the Cubs confident? Time will tell.