This one was close. I strongly considered going with Christian Vazquez. He quickly became one of my favorite players of the year with his out-of-nowhere 23 home runs. But Vazquez had a very good season in 2017. Brandon Workman on the other hand shocked everyone.
Workman was a second-round draft pick by the Red Sox in the 2010 draft. He kind of went unnoticed for much of his minor league career, never really achieving any sort of top prospect status but he had some solid numbers. He made the jump to the Majors in 2013 and put together a decent season. He even pitched in the postseason, appearing in seven games (including three in the World Series) without giving up a single run. It was anticipated that he would be a big part of the 2014 staff.
Things did not work out for Workman in 2014 though. He was in the starting rotation, but went just 1-10 with an unsightly 5.17 ERA. His strikeout rate collapsed. Then he was injured for the entire 2015 season. Not much was expected from Workman from that point on, but he made it back to the Majors in the bullpen in 2017, becoming a reliable arm again. 2018 was more of the same, but no one could have predicted the year he would have in 2019.
The Red Sox did not do much to improve their bullpen prior to the 2019 season, even though the team lost both Joe Kelly and Craig Kimbrel to free agency. Workman quickly became the most reliable arm in the bullpen and eventually worked his way into the closer role. He only saved 16 games, but he did two rare things for a reliever: he won ten games without starting a single one and he struck out over 100 batters. His final numbers were surprisingly great, one of the better relief seasons for the team in recent years. Workman finished the year 10-1 with a 1.88 ERA and 104 strikeouts compared to 45 walks in 71.2 innings. He will start the 2020 season as the favorite to be the team's closer.