Justin Wilson is proof that not everything Theo Epstein touches immediately turns to gold.

Though, that's not to say it's the fault of Epstein or the Cubs' front office.

Who could've possibly predicted Wilson's epic struggles in Chicago after pitching well with the Detroit Tigers earlier in the season?

When Epstein and Co. traded for the dynamic left-handed reliever, he was one of the top high-leverage pitchers in baseball — sporting a sparkling 0.94 WHIP, 2.68 ERA, 13 saves and 55 strikeouts against only 16 walks in 40.1 innings.

But in Chicago, Wilson was suddenly ineffective. He managed just 53 outs in 23 appearances, walking 19 batters and serving up 18 hits in 17.2 innings. His strikeouts actually went up a tick, but the lack of control was alarming.

Things got so bad, Wilson was used to get just two outs in the postseason and wasn't even active for the National League Championship Series against the Los Angeles Dodgers.

Yet none of that has scared the Cubs off from counting on Wilson to be a big part of the 2018 bullpen.

"I think you will [see a rebound]," GM Jed Hoyer said. "Sometimes guys come to a new place, they get off to a rough start and that kinda snowballs on them. When you look at his track record, there's no reason in the world to think he won't be pitching late in the game or won't have a big role.

"That's what he's done his whole career except for the blip with us and I think he'll get right back to doing that again."

But Wilson wasn't the only Cubs reliever who struggled with walks. It was a bullpen-wide issue in 2017 — a problem the Cubs hope to correct in 2018, in part due to a new pitching coach (Jim Hickey) providing a different voice.

Dig deeper, however, and it's clear to see Wilson's issue wasn't only that he forgot how to throw strikes.

In Detroit, 36.9 percent of pitches Wilson threw were balls. In Chicago, that number rose to 42 percent, which is only a difference of 5 extra balls every 100 pitches thrown.

That's not enough to account for such a huge increase in walks. So what gives?

A huge part of the problem was a precipitous dip in batters swinging at pitches Wilson threw out of the zone. Over his career, Wilson has hovered around batters swinging at his pitches out of the zone around 1/3 of the time. In Chicago batters swung less than 1/4 of the time at pitches out of the zone.

That may be because he started throwing his fastball a lot more with the Cubs and relied less on his breaking stuff (slider and cutter). He has rarely thrown his changeup in his career, but never even tried it with the Cubs.

What it boils down to is fastball command, which Joe Maddon typically points to first whenever a pitcher is experiencing inconsistency on the mound. Wilson didn't always know where his fastball was going, which means his breaking stuff didn't play as well in conjunction with that and he was thus forced to throw his fastball more often just to try to get more strikes.

Now that they're not in the middle of a pennant race, both Wilson and the Cubs have had time to digest what went wrong. The organization is optimistic good times are coming, mostly because they see the issues as clearly fixable.

"Oh sure. No question," Hoyer said. "We saw some glimpses at the end. You've seen it happen enough times that a guy gets off to a bad start.

"It's all fixable. We still feel the same way about the player. I think coming into a new season, a new spring training, a new pitching coach — I think that's all positive."

The "new season" part may be the biggest factor working in Wilson's favor.

There's no doubt his struggles last fall got inside his head. How could they not?

But a new year means time to hit the reset button on the confidence and mental side of the game, which can make all the difference.

"If things don't get off on the right foot, they probably try too hard," Hoyer said. "They want to impress their teammates and it can go south on them. It's not the first time [this has happened].

"I have a ton of confidence in him. This guy's had a really good career — pitched late in the game for a long time. There's no reason to think he won't come in and be good for us next year."