What a difference a year makes. In 2015, Rick Porcello had one of the worst seasons of his MLB career. In 2016, the Boston Red Sox ace is the American League Cy Young Award winner.

MLB shared the news on Twitter:

Below are the full results from the Cy Young vote, per the Baseball Writers’ Association of America:

Based on this year’s numbers, Porcello’s win wasn’t a surprise. At the least, he was as good as fellow finalists Justin Verlander and Corey Kluber:

At the beginning of the season, many fans in Boston likely expected a Red Sox starting pitcher to be among the Cy Young finalists. The team spent $217 million in the offseason to have David Price anchor the rotation, in part due to Porcello’s lackluster first year with the team.

However, Price and Porcello swapped roles. The latter became Boston’s best pitcher, while the former was a high-priced disappointment.

During his six years with the Detroit Tigers, Porcello showed signs of promise but often failed to find much consistency from one start to the next. The Red Sox acquired him in December 2014 and signed him to a four-year, $82.5 million deal the following April.

At the time, the contract looked risky, and Boston may have had buyer’s remorse after Porcello finished 2015 with a 9-15 record and a 4.92 ERA.

In an interview with the Boston Globe‘s Alex Speier, Porcello said he felt a lot of pressure during his debut campaign with the Red Sox:

I wouldn’t say that the contract itself entirely was a factor last year. I think that coming to a new place, teammates, organization, fans, all of that collectively, Boston, the Red Sox, all of that collectively was something that I have a lot of respect for. I wanted to put my best foot forward. It really took an adverse effect. It kind of got worse and worse as the season went on. The more I tried to get better and produce, it didn’t happen. It went in the opposite direction.

Porcello’s improved level of comfort showed in his walk rate. He averaged a career-low 1.29 walks per nine innings in 2016.

His turnaround will provide optimism to the team, which will hope Price has a similar improvement in his second year with the Red Sox.

The big question will be how much—if any—Porcello’s performance was an outlier relative to the rest of his career.

Cliff Lee had a similar arc with the Cleveland Indians. He went from having a 6.29 ERA in his age-28 season in 2007 to winning the 2008 Cy Young before cementing himself as one of MLB’s best pitchers.

Porcello has always had the tools to become a top-end starter. Now, he may be putting it all together.

As much as they spent to bolster the rotation last year, starting pitcher is an area of concern for the Red Sox. Clay Buchholz continues to be erratic, and the Drew Pomeranz trade was a flop in the second half.

If Porcello carries his 2016 numbers over to 2017, then he can help compensate for the rest of the rotation’s problems. Should he regress back to previous years, though, it will further exacerbate the problem.

              

Stats are courtesy of FanGraphs unless otherwise noted.

Read more MLB news on BleacherReport.com