By Bruce Levine–

MESA, Ariz. (CBS) — Many experts have already tabbed the Cubs as favorites to win the 2016 World Series. With that in mind and the ultimate goal clearly set, there are areas of depth that still may need to be addressed.

Defense is king for championship clubs, and if the Joe Maddon 25 are going to go wire to wire in the 162-game marathon and ensuing postseason, solid outfield defense will be needed.

As a strong team enters spring training, that’s a glaring area that stands out as a somewhat unknown quality. After the addition of Jason Heyward and the subtraction of Dexter Fowler and Austin Jackson, the outfield defense has a new look and carries some questions. The progress of young corner outfielders Jorge Soler and Kyle Schwarber will help determine the real need for a trade during the spring and into the long season. The multi-positional Chris Coghlan will add his solid bat and clutch hitting to the mix too.

A center field backup will be crucial for the Cubs, a club that would prefer to play Gold Glove right fielder Heyward on the corner rather than in center.

“I have a good grasp of center field,” Heyward said Friday. “Right field is pretty much me, so I am good there. As far as playing center, I need to just take more reps. I know the basics of center. I just need to act it out and after that, it will become home.”

The wild-card players in this process are Matt Szczur and Javier Baez. Szczur’s a good defender who has yet to get many at-bats in the major leagues. Baez will get a tremendous amount of work in the outfield this spring that will help determine if he can play center field and push the other two young outfielders for playing time.

Baez played a handful of games in the outfield in winter ball this offseason, and Maddon would love to see him turn into the next super-utility man. Maddon would use him in a similar manner that he used new Cubs second baseman Ben Zobrist in Tampa.

Both Soler and Schwarber have worked hard on their outfield bursts and conditioning this offseason. President of baseball operations Theo Epstein said last month that Soler had lost weight and redistributed his body strength after working all winter in Florida.

A second-year pro, Schwarber also changed his routine. He’s preparing to get better at both catcher and in the outfield.

“This morning I was a catcher,” Schwarber said Friday. “I am still a catcher. I worked all offseason on getting better at two positions. Anything can happen. Last year (Miguel Montero) got hurt, and I got called up to catch. Anything can happen and if anything like that happens again, I have to be ready. So I still am going to prepare like I am a catcher and still try to get better in the outfield.”

The 34-year-old Zobrist is the fail safe for Maddon and his use of outfield depth. He can handle all three outfield positions and is above-average on the corners. Albert Almora, the team’s 20212 first-round pick, is on a fast track to the major leagues after finishing last season at Double-A. Matt Murton was also signed as potential depth option for a corner outfield spot, and he’ll get a chance to prove himself in spring training.

Bruce Levine covers the Cubs and White Sox for 670 The Score and CBSChicago.com. Follow him on Twitter @MLBBruceLevine.