When the 2017 season ended, Cubs left fielder Kyle Schwarber looked in the mirror and didn't like what he saw.

He was stocky, slower than he wanted to be and he had just finished a very difficult season that saw him spend time back in the minor leagues at Triple-A after he struggled mightily through the first three months of the season.

Schwarber still put up solid power numbers despite his overall struggles. He slammed 30 home runs, putting him among the Top 15 hitters in the National League and among the Top 35 in all of baseball. But, Schwarber was honest with himself. He knew he could achieve so much more if he was in better shape and improved his mobility, his overall approach at the plate and his defense.

Schwarber was drafted by the Cubs out of Indiana University as a catcher. However, many scouts around baseball had serious doubts about his ability to catch at the big league level. The Cubs were in love with Schwarber the person and Schwarber the overall hitter and felt they would give him a chance to prove he could catch for them. If he couldn't, then they believed he could play left field adequately enough to keep his powerful bat in the lineup.

However, a serious knee injury early in the 2016 season knocked Schwarber out of action for six months and his return to the Cubs in time to assist in their World Series run raised expectations for a tremendous 2017 season. In fact, the expectations for Schwarber were wildly unrealistic when the team broke camp last spring. Manager Joe Maddon had Schwarber in the everyday lineup batting leadoff and playing left field.

But Schwarber's offseason after the World Series consisted of more rehab on his still-healing injured left knee. That kept him from working on his outfield play, his approach at the plate and his overall baseball training.

Add in all of the opportunities and commitments that come with winning a World Series and it doesn't take much detective work to understand why Schwarber struggled so much when the 2017 season began. This offseason, though, has been radically different. A season-ending meeting with Cubs president Theo Epstein and general manager Jed Hoyer led to a decision to take weight off of Schwarber's frame. It also included a decision to change his training program so that he improved his quickness, lateral movement and his overall baseball skills.

"I took two weeks off after the season ended and then I went to work," Schwarber said. "We put a plan together to take weight off and to improve my quickness. I have my meals delivered and I feel great. My baseball work combined with a lot of strength and conditioning has me in the best shape that I have ever been in."

Schwarber disagrees with the pundits who felt manager Maddon's decision to put him in the leadoff spot in the Cubs' loaded lineup contributed to his struggles.

"I have no problem hitting wherever Joe wants to put me," Schwarber said. "I didn't feel any more pressure because I was batting leadoff. I just needed to get back to training for a baseball season as opposed to rehabbing from my knee injury. I'm probably 20-25 pounds lighter and I'm ready to get back to Arizona with the boys and to get ready for the season."

Many around the game were shocked when the Cubs drafted Schwarber with the No. 4 overall selection in the 2014 MLB Draft, but a rival executive who was not surprised by the pick believes that Schwarber can indeed return to the form that made him such a feared hitter during his rookie season as well as his excellent postseason resume.

"Everyone who doubted this kid may end up way off on their evaluation because he is a great hitter and now that he is almost two years removed from his knee injury," the executive said. "He knows what playing at the major-league level is all about I expect him to be a real force in the Cubs lineup.

"Theo and Jed do not want to trade this kid and they are going to give him every opportunity to succeed. I think he has a chance to be as good a hitter as they have in their order."

Watch the full 1-on-1 interview with Kyle Schwarber Sunday night on NBC Sports Chicago.