Welcome to the 2021 positional preview series. Over the next seven days, we will be looking at each position group catcher Hunter Renfroe Face Mask, corner infield, middle infield, corner outfield, center field, starting pitchers, and relief pitchers throughout the organization. For each installment we will take a look at the projected starter Darwinzon Hernandez Face Mask, the options to come off the bench, the depth pieces who will be waiting at the Alternate Site/at Triple-A, the top prospect, the sleeper prospect, and all the rest of the prospects for each position. Today we finish things up with a look at the relief corps.Starters Matt Barnes, Adam Ottavino, Darwinzon Hernandez, Hirokazu Sawamura, Josh Taylor, Matt Andriese, Garrett Whitlock, Austin Brice, Ryan BrasierPerhaps the most intriguing roster question on this alum, he the best non-Bazardo prospect in this group with a really good fastball/slider combo that is so common late in games these days. He can be a late-inning arm, but still needs a little more refinement. He start the year in High-A, but could be a quick mover.Durbin Feltman was supposed to be the big relief prospect for the Red Sox as a third round pick in 2018, but his first full season as a pro was a major disappointment as he couldn command anything. The good news is the stuff reportedly looked better at Instructs, and I like him as a post-hype sleeper this year that could very well make an impact in the majors at some point in the summer if things break right https://www.baseballstoreonline.com/Chris_Sale-228.Brendan Cellucci is the best left-handed reliever in the organization, and the former 12th rounder is looking to make his full-season debut this year after being drafted in 2019. He has a big fastball, but he needs to sharpen up his secondaries, which consist of a slider and a changeup.