I considered going with Steve Pearce here, but winning the World Series MVP kind of disqualified him. There really is no one better than Ryan Brasier anyway.
Brasier had a long, winding road to make it to the Majors this year. He was originally drafted by the Angels in the sixth round of the 2007 Draft. It took several years but he made it to the Majors in 2013 with the Angels. He appeared in just seven games as a reliever. He threw nine innings, striking out seven and walking four with a 2.00 ERA. He then missed all of 2014.
The Athletics grabbed him as a minor league free agent in 2015 and he spent the next two seasons in the minors. In 2017 he went to Japan to play for the Hiroshima Carp. He pitched well enough that the Red Sox took a flyer on him for the 2018 season. He spent Spring Training mostly as a closer and was assigned to Pawtucket once the season started. He pitched so well in Pawtucket (13 saves, 1.34 ERA) that he got the call-up to Boston.
The 30-year-old gradually built up enough trust that he started getting thrust into more and more important situations. Brasier soon became a set-up man. For the season, he pitched in 34 games with a 2-0 record and a 1.60 ERA. He struck out 29 batters while walking just seven batters in 33.2 innings. Surprisingly, he is still technically eligible as a rookie in 2019.
The biggest sign of the trust he had gained from his manager was his inclusion on the post-season roster. Brasier struggled a bit in his first appearance, but was able to adapt. His barking at Gary Sanchez to get in the box and stop stalling endeared him even more to his teammates and fans. He appeared in nine games in the postseason, with a 1.04 ERA and seven strikeouts.
There is no way to be sure what Brasier will become, but he had a terrific 2018 season, capped off by being on a World Championship team. Hopefully he will get a Major League card made soon. Maybe in 2019 Topps or Heritage.