Replacing 339 innings from the starting rotation will be the biggest challenge for the Cubs front office this season. That’s how many innings that right-hander Jake Arrieta and right-hander John Lackey combined to log in 2017. With Arrieta expected to be too costly for the Cubs in free agency and many believing Lackey will retire, Cubs executives Theo Epstein and Jed Hoyer must concentrate on addressing the rotation holes. The pitching in the Cubs’ farm system has shown promise and been praised, but it’s still not ready for the big leagues yet. So the Cubs will need to rely on trades and free agency this offseason to add a couple starters and also address a bullpen that needs shored up. The Epstein-Hoyer regime is one that has traditionally proved to be proactive. Already since being eliminated from the playoffs, the Cubs have agreed to a deal with Jim Hickey to become their new pitching coach after the exit of Chris Bosio. Hickey has a great reputation for fixing talented-but-flawed relievers. On top of that, there are several pitchers in Tampa Bay, where Hickey coached the past 11 seasons, who could help Chicago address the likely losses of Arrieta, Lackey and closer Wade Davis as well. In his end-of-season press conference, Epstein made clear the Cubs want Arrieta and Davis back while adding there’s only so much they can control. Arrieta was 14-10 with a 3.53 ERA and 1.22 WHIP in 30 starts. Davis had 32 saves, a 2.30 ERA and 1.14 WHIP in 58 2/3 innings. “We would love to have Wade Davis back and the same for Jake,” Epstein said. “They are two quality pitchers and are elite at what they do. They have tremendous track records. We all know that it is more complicated than that. Wanting doesn’t mean having. It is a complicated landscape in the offseason. Free agency is a right that is earned. Sometimes you only get one crack at it. They must do what they should do going forward for themselves and their families. From our perspective, we would love to have them both back.” The Cubs must make some tough choices on spending both money and player assets. By acquiring left-hander Jose Quintana from the White Sox in a July trade, they’ve assured themselves a quality starting pitcher under team-friendly contract control for the next three years. It’s expected the Cubs will try to make another similar move, perhaps chasing Giants right-hander Jeff Samardzija (three years, $59 million left on his deal) or Rays right-hander Chris Archer (four years and $34 million left if two team options are exercised).