Miles: Who is the ace of this Cubs staff?

The title of "ace" of a pitching staff is pretty much a mythical one.

Ask any pitcher or manager who the ace of the staff is and he'll tell you it's whoever takes the mound on that particular day or night.

Even though the title of ace is bestowed on a pitcher before the season starts - and that guy pitches on Opening Day - more often than not, the ace emerges by performance.

So who is the ace of the Cubs staff just more than one-third of the way through the 2015 season?

Well, the Cubs signed lefty Jon Lester to a six-year, $155 million contract last winter to be their ace, but Lester is off to a lackluster start, going 4-5 with a 4.25 ERA and a WHIP of 1.43

Jake Arrieta, who started Wednesday night's game at Detroit, emerged as the ace last year, and he's done little to lose it, even though Jason Hammel has returned to the Cubs and staked his claim.

Arrieta worked 6 innings against the Tigers in the Cubs' 12-3 victory. His record improved to 6-4 with a 3.16 ERA. Arrieta also took over the team lead in quality starts, with 9, as he gave up 8 hits and 3 runs. The Cubs supported Arrieta with 4 runs in the third inning. He gave up a 3-run homer to Yoenis Cespedes in the sixth, but the Cubs responded with a 6-run seventh.

Hammel has been nothing short of a revelation in his second stint with the Cubs. He is 5-2 with a 2.76 ERA and an 0.89 WHIP, which leads the National League. Hammel went 8-5 with a 2.98 ERA for the Cubs last year before he was traded to Oakland on July 5 in team president Theo Epstein's "Last Great Midseason Sell-off."

Although Hammel went 2-6 with the Athletics, something about pitching for the Cubs seems to agree with him.

Lester still has plenty of time to right himself, and if he does, it's likely nobody on the staff will care who's called the ace.

Drafting is done:

Major League Baseball concluded its amateur draft Wednesday with rounds 11-40. In the 14th and 15th rounds, respectively, the Cubs selected right-handed pitchers Jake Kelzer and Scott Effross out of Indiana University.

Both pitchers were teammates of catcher Kyle Schwarber, the Cubs' No. 1 pick last year. Schwarber is playing well at the Cubs' Class AA Tennessee affiliate.

In the 32nd round, the Cubs took right-hander Fitz Stadler out of Glenbrook South High School in Glenview. Stadler, who has committed to Arizona State, was 8-0 with an 0.81 ERA this high school season.

The Cubs chose 18 pitchers, four catchers, eight outfielders an 10 infielders. They took 29 college players, 10 high schoolers and one without a school affiliation.

Bleachers are back:

The Cubs return to Wrigley Field Thursday evening to play the Reds. One month after the rebuilt left-field bleachers opened, the new right-field bleachers will reopen. The Cubs are embarking on a multiyear renovation of the 101-year-old ballpark.

They had hoped to have all of the bleachers ready by Opening Day, but bad winter weather and a water-main issue delayed the initial phase of the project.

Cubs scouting report

CUBS vs. Cincinnati Reds at Wrigley Field

TV: Comcast SportsNet tonight; WGN Friday; FOX Saturday; ESPN Sunday

Radio: WBBM 780-AM

Pitching matchups: The Cubs' Tsuyoshi Wada (0-1 vs. Michael Lorenzen (1-1) tonight at 7:05 p.m.; Jason Hammel (5-2) vs. Johnny Cueto (4-4) Friday at 3:05 p.m.; Kyle Hendricks (2-2) vs. Mike Leake (3-4) Saturday at 6:15 p.m.; Jon Lester (4-5) vs. Anthony DeSclafani (5-4) Sunday at 7:08 p.m.

At a glance: The road-weary Cubs come home after playing nine away from Wrigley Field. Tonight's game will be the third in a stretch of 20 in a row and the first of eight straight against Ohio opponents. The Reds have played better of late. Joey Votto, who hit 3 homers Tuesday against the Phillies, entered Wednesday leading the team in on-base percentage (.405). Todd Frazier led in homers (17), RBI (37) and hits (64), while Brandon Phillips led in batting average (.308). Zack Cozart had to leave Wednesday's game against the Phillies with a right-knee injury. The Cubs have struggled against the Reds in recent years, but they're off to a 4-1 start against Cincinnati this season, 2-1 at Wrigley Field.

Next: Cleveland Indians at Wrigley Field, Monday-Tuesday

- Bruce Miles