BOSTON -- You had a feeling that 2019 would be a breakout season for Rafael Devers. But nobody could have predicted Devers was going to go off to the degree that he did.

The left-handed slugger had one of the best seasons in history for a 22-year-old.

Consider the following: Devers became just the 10th player to hit .300 with 30-plus homers, 100-plus RBIs and 100-plus runs scored in a season before turning 23. Ted Williams, Jimmie Fox, Alex Rodriguez and Albert Pujols each did it twice. Devers is the first to accomplish the feat since Miguel Cabrera in 2005.

The exciting thing is that Devers is still evolving, and the Red Sox likely haven’t seen what he is fully capable of just yet.

“I want to improve on everything,” said Devers. “Just because I had a good season this year doesn’t mean there aren’t things I can’t improve from defense to offense. I just want to improve everything going into next season.”

What went right?

Quite a bit. Devers was a machine at the plate, hitting for average (.311), power (32 homers) and all those doubles (54).

“Overall, offensively, I feel like I’m proud of everything I’ve been able to do,” said Devers. “I give a lot of credit to Xander [Bogaerts], who has helped me a lot with my preparation and just everything he’s been able to help me with. Just, offensively, I had a really good season and I think I was able to have an overall season that I’m really proud of.”

It was on defense where Devers made his best improvement. He became a liability at times last year, all too frequently making routine errors. After a tough first month in 2019, Devers cleaned it up the rest of the way and excelled in the field. Coaches Carlos Febles and Ramón Vázquez spent a lot of time working with Devers on his defense.

“It just all comes down to the experience [on] defense,” Devers said. “I know there were some errors I was making last year where I was just like, ‘Man, how did I make that?’ This season, I know I’ve improved. Obviously I’ve made some errors here and there. But I’ve just continued to learn on how to improve.”

What went wrong?

Devers isn’t disciplined at the plate on a consistent enough basis. Manager Alex Cora constantly talks about controlling the strike zone. When Devers isn’t able to do that, he gets exposed.

For Devers to reach the level of Nationals star phenom Juan Soto, he needs to swing at his pitch, not the one at which the pitcher wants him to swing. Devers had 119 strikeouts and just 48 walks in 702 plate appearances.

Best moment

There were many great days from Devers in 2019, but it’s easy to find the one that tops the list. On Aug. 13, Devers went 6-for-6 with four doubles to help fuel the Red Sox to a 7-6 win over the Indians in 10 innings. The performance was historic, as Devers became the first player to record six or more hits and four or more doubles in the same game.

2020 outlook

If J.D. Martinez opts out of his contract and leaves the Red Sox, the importance of Devers as a run producer will grow. The Sox need Devers to be a force in the middle of the batting order -- and not just in 2020, but for the next several seasons. If he can take the next step and improve his ability to control the strike zone, Devers should become an American League All-Star for the first time.