Ostrowski: Are the Chicago Cubs hunting for a new ace?

Are the Cubs going ace hunting?

Theo Epstein and company will add starting pitching. It isn't a need, it's a must.

Jake Arrieta, John Lackey, and Brett Anderson will be free agents at the end of the season. Right now, they could use one starter for this year and two for 2018, at least. Epstein was up front about that fact with "Mully & Hanley" on 670 The Score.

"At some point, we're gonna be able to pull off a deal where we trade some position player resources, probably in the form of prospects, for starting pitching to help our big league club either in the present or in the future or hopefully both."

The top of the 2018 free agent class looks to be the Royals' Jason Vargas and Blue Jays' Marco Estrada. Vargas' 1.01 ERA is baseball's best by a wide margin and Estrada was an all-star last year. Both pitchers are approaching their mid-30s.

The Cubs might have something in Eddie Butler and/or Mike Montgomery, but that isn't enough. Both are under team control through 2021.

There are a few number one starting pitchers that could be available: Gerrit Cole, Johnny Cueto, Sonny Gray, and yes, Jose Quintana anyone?

Pittsburgh is in the NL Central cellar and need to figure out if they'll be able to sign Cole or if they should just flip him now. San Francisco has the worst record in baseball. Gray has been connected to the Cubs for years and maybe pitching coach Chris Bosio can get him back on track. Quintana probably won't happen, but the White Sox have a price tag on everything at their garage sale.

ESPN's Keith Law talked about a surprising Cubs rumor on Buster Olney's podcast. "I'd heard specifically they were scouting Zack Greinke pretty heavily in spring training; more than just ordinary spring training coverage. And that that was part of a plan to go out and scout pitchers with multiple years of control remaining and potential to be a one or two starter in their rotation."

Now that would shock the baseball world. Greinke signed a 6-year, $206.5 million dollar contract just over a year ago with the Diamondbacks. They are in the playoff race, but something to watch for if the Rockies and/or Dodgers separate themselves from Arizona in the NL West.

Greinke took a no-hitter into the 8th inning in his last start. After a subpar 2016, it looks like the old Greinke is back. With a 1.9 WAR, he's already nearly matched his 2.3 from a year ago.

The days of adding a Dan Haren are long gone. It isn't a matter of if, but when the Cubs are going to strike.

• Joe Ostrowski is a co-host of the "Hit & Run" baseball show from 9 a.m. to noon Sundays on WSCR 670-AM The Score with Barry Rozner. Follow him on Twitter@JoeO670.