Kimbrel anchors Red Sox's strong 2018 'pen

BOSTON -- It comes at you with waves of heat, this Boston bullpen. And by the ninth inning, Craig Kimbrel is mixing his 98-mph fastball with a knuckle curve that ties hitters in knots.
The bullpen should once again be a strength for the Red Sox in 2018, as every key member is back except for free-agent right-hander Addison Reed.
Carson Smith should be there for a full season this time, now fully recovered from Tommy John surgery. Former starting pitcher Joe Kelly is now entrenched as a reliever, and he throws with triple-digit velocity at times.
The one thing president of baseball operations Dave Dombrowski is looking to add to the group is a standout lefty to complement the impressive collection of righties.
BULLPEN IF SEASON STARTED TODAY
Craig Kimbrel, RHP
Carson Smith, RHP
Joe Kelly, RHP
Matt Barnes, RHP
Heath Hembree, RHP
Brandon Workman, RHP
Robby Scott, LHP
STRENGTH
Kimbrel is a force in the prime of his career, and his 2017 season was one of the best by a reliever in Red Sox history. In 69 innings, Kimbrel had a whopping 126 strikeouts and a microscopic WHIP of 0.68. He struck out 16.4 batters per nine innings. Perhaps most impressive was Kimbrel's utter dominance against right-handed hitters, who posted a feeble .109/.156/.180 slash line against him. New manager Alex Cora is going to look for opportunities to bring Kimbrel on more often in the eighth inning when the situation presents itself. If Kimbrel continues at his current pace, he will build a strong candidacy for the Hall of Fame. Over eight seasons, his ERA is 1.80.

QUESTION MARK
Who will be the primary setup man? Reed served that role the final two months of last season following his acquisition from the Mets, but he seems likely to land elsewhere as a free agent. It would be fitting if Smith wound up taking over in the eighth because that's the role the Red Sox got him for in the first place, only to lose him for most of 2016 and '17 due to Tommy John surgery. Kelly and Barnes both have the power stuff to pitch in the eighth, but they also are valuable serving in a multi-inning role.
WHAT MIGHT CHANGE
A deep setup crew could get even deeper if Tyler Thornburg can make it back from the thoracic outlet syndrome procedure he had on his right shoulder last summer. Thornburg was acquired from the Brewers for Travis Shaw to be the lead setup man in 2017, but he missed the entire season. The Red Sox are cautiously optimistic he will be healthy for Spring Training.
The one thing Dombrowski would like for his bullpen is a little more right-left balance. The search for a lefty has been slow going so far, but it should be fruitful at some point this offseason. Tony Watson, Brian Duensing and Oliver Pérez are available via free agency. If Dombrowski can't acquire a left-hander, the Red Sox might explore converting starter Brian Johnson into a reliever. Johnson works fast and throws strikes, two traits that generally play well out of the bullpen. He has seemingly been on the cusp of helping the Red Sox as a starter, but he has gotten held back by untimely injuries. Moving to a relief role might allow his arm to hold up better.