CHICAGO -- Addressing pitching depth was a major offseason goal for the world champion Chicago Cubs, and now that spring training is nearly upon us we can assess whether they’ve fortified themselves enough for the approaching marathon. Remember, the Cubs now view the season as a seven-month exercise -- not just the usual six months and 162 games. They expect playoff baseball again.

With a farm system that is still attempting to churn out major league-ready starters, the front office picked up two more arms in recent days -- right-handers Eddie Butler and Alec Mills. Both were designated for assignment by their former teams, but the Cubs didn’t wait and traded their own prospects to acquire the pitchers -- an indication that other teams probably had interest in those players.

"Both were getting phone calls," Cubs general manager Jed Hoyer said Thursday on ESPN 1000. "They have options. They can make starts for you. Finding guys who can make starts for you is very difficult and very expensive. We showed the appropriate urgency to get those guys."

"Options" is a key word, because the Cubs are pretty set at the major league level, but if there’s an injury to a starter, they need to turn to a reliable arm or two. They think Butler and Mills can join a handful of other Triple-A guys whom manager Joe Maddon can turn to if needed. Mills has impressed with a good changeup after being drafted in the 22nd round; to get him, the Cubs gave up a second-rounder, outfielder Donnie Dewees.

Meanwhile, Butler was a highly touted prospect who never got to the next level with the Rockies.

"He’s an excellent change-of-scenery guy," Hoyer said of Butler. "Our best example is Jake Arrieta. Sometimes a talented guy needs a change of scenery, and that was our logic with Eddie Butler."

Hoyer indicated the Cubs have been interested in Mills for quite a while as his name came up in discussions with the Royals while the teams prepared an earlier offseason trade; the Cubs acquired reliever Wade Davis from Kansas City for outfielder Jorge Soler. The irony about Mills is that he became available when the Royals signed Jason Hammel this week. The Cubs let him go when they declined his option for 2017.

"We think he can fit in nicely as a guy that provides depth," Hoyer said of Mills. "If we have injuries at the major league level, he can come up and help us out."

Would the staff be better -- and deeper -- if Hammel were still in the rotation? The Cubs' stated goal all winter was to find reliable starters, yet they said goodbye to a serviceable pitcher who was going to make "only" $10 million. Though he had an elbow tweak at the end of the season, Hammel was pretty reliable during his time with the Cubs, making a total of 61 starts over the past two years. But the team did him a favor by letting him go, partly to allow him to test free agency and earn some more security, but also because it was time for a change of scenery.

It became obvious -- and at times public – that Hammel and his manager didn’t see eye to eye. Maddon pulled the right-hander from several games earlier than the pitcher would have liked. Hammel didn't make any of the postseason rosters. So after the World Series, the Cubs gave him the choice. He chose to leave, and sources close to the situation say that choice was as much about Maddon as anything else. That can’t come as a big surprise to those who have followed the drama for two seasons. Hammel simply felt his manager lost faith in him, and at that point it was time to go.

Without Hammel -- and with Butler and Mills in the fold -- here is an unofficial look at the depth chart for Cubs starters Nos. 5 through 10 when camp opens Tuesday: Mike Montgomery, Brett Anderson, Rob Zastryzny, Butler, Mills and prospect Ryan Williams. After Nos. 5 and 6, it’s a toss-up as to who the Cubs would turn to in a pinch -- that’s what spring training and the early portion of the season is for. And changes to the plan are always possible. For example, if Zastryzny is needed in the bullpen, that could take him out of the starting mix.

Will it be enough for a team attempting to repeat as champion? It’s obvious, even this late in the offseason, that the Cubs were not thrilled with their depth, but they’re better today than they were a week or two ago. Plus, pitching coach Chris Bosio has worked wonders these last few years, so the Cubs are counting on him to bring out the best in their new arms. Otherwise, they might be right back on the trade market before long. The search for pitching is never-ending.