Building a bullpen is an inexact science. It also can be the difference between fielding a legitimate World Series contender and sitting at home come October.

The Red Sox’s relief corps, fairly or unfairly, was criticized ad nauseam in 2019 following the offseason departures of closer Craig Kimbrel and setup man Joe Kelly. One could make the case the starting rotation was the team’s fatal flaw. But the bullpen wasn’t far behind, as a rotating cast of underwhelming options made its way through Boston with limited success.

Brandon Workman was excellent, ultimately establishing himself as the Red Sox’s closer. Beyond that, Boston’s ‘pen is littered with question marks, even though a few relievers, including soon-to-be sophomore Darwinzon Hernandez and returning veteran Matt Barnes, carry some level of upside.

Basically, new chief baseball officer Chaim Bloom has his work cut out for him this offseason. And improving the Red Sox’s bullpen is further complicated by the organization’s payroll constraints, which could prevent Boston from making a splash on the free agent market unless Bloom significantly overhauls other areas of the roster.

The most likely scenario is the Red Sox address their bullpen through the trade market and/or low-cost options in free agency, thus making it nearly impossible to project who they’ll target. But it’s still worth perusing the reliever landscape in case Boston does dip its toes into free agency.

As such, here are some relief pitchers available in free agency, along with their apparent standing in the marketplace relative to the Red Sox’s current situation.

Pie in the sky
1. Will Smith, LHP

Smith is the best free agent reliever available now that Aroldis Chapman has agreed to a contract extension with the New York Yankees and Kenley Jansen isn’t opting out of his contract with the Los Angeles Dodgers. He’ll be rewarded as such, with MLB Trade Rumors predicting a three-year, $42 million deal for the 30-year-old closer and FanGraphs projecting a three-year, $36 million payday.

Smith could accept the San Francisco Giants’ one-year, $17.8 million qualifying offer or seek a multiyear deal on the open market. He’s almost certainly out of Boston’s price range, though, especially when you factor in the draft pick compensation that’s now attached to him by virtue of that qualifying offer.

Second-tier options
2. Will Harris, RHP
3. Dellin Betances, RHP
4. Daniel Hudson, RHP

Harris probably is the second-best reliever available in free agency, even though the lasting image of Game 7 of the 2019 World Series is him surrendering a go-ahead home run to Howie Kendrick. Like Smith, Harris likely is out of the Red Sox’s price range, with MLB Trade Rumors giving him a two-year, $18 million contract and FanGraphs tabbing him with a two-year, $20 million deal.

Betances and Hudson seem more realistic, although the former’s market is difficult to gauge given that he appeared in just one game in 2019 but otherwise had dominant stretches over his previous five seasons with the Yankees. And the latter surely earned himself a few extra bucks based on his performance with the Washington Nationals, particularly during the playoffs, following a midseason trade from the Toronto Blue Jays.

Notable swingmen
5. Drew Pomeranz, LHP
6. Collin McHugh, RHP

Most Red Sox fans are familiar with Pomeranz’s work, for better or worse, although it might come as somewhat of a surprise that he actually excelled out of the bullpen for the Milwaukee Brewers in the second half of 2019 and therefore is one of the more intriguing relief options available this winter.

The same goes for McHugh, who thrived as a reliever in 2018 (1.99 ERA in 72 1/3 innings) and stunk upon transitioning back to the rotation in 2019, only to find success again once the Houston Astros removed him from a starting role in early May.

Both pitchers are worth noting given their ability to go multiple innings in relief and serve in a swingman capacity, especially with so many questions in the Red Sox’s rotation thanks to injuries and inconsistency plaguing Chris Sale, David Price and Nathan Eovaldi in 2019.

Other possible fits
7. Sergio Romo, RHP
8. Joe Smith, RHP
9. Chris Martin, RHP
10. Craig Stammen, RHP
11. Pedro Strop, RHP
12. Brandon Kintzler, RHP
13. Arodys Vizcaino, RHP

This really is a take-your-pick group that could be extended even further based on the sheer volume of arms available. It speaks to the year-to-year volatility of the relief market in general, although front office executives across Major League Baseball are paid big bucks to navigate these muddy waters and identify low-cost, high-upside relievers capable of bringing stability to the bullpen.

Romo is a name Bloom certainly is familiar with from his time in the Tampa Bay Rays front office. The right-hander served as an opener, a closer and everything in between for the Rays during the 2017 and 2018 seasons before spending 2019 split between the Miami Marlins and Minnesota Twins. He’s a low-cost option whose versatility could be valued as the Red Sox shape their bullpen.

Smith, who turns 36 in March, is a journeyman, having played for six teams in his 13-year career. But he also is dependable, featuring a sidearm delivery and an ability to retire both left-handed hitters and right-handed hitters.

Martin, another right-hander, has had an interesting baseball journey, but the fact is he strikes out many, walks few and comes with the type of late-inning upside several aspiring contenders will covet.

Stammen spent his last three seasons with the San Diego Padres, posting a respectable 3.06 ERA, 3.57 FIP and 1.13 WHIP across 209 appearances.

Strop is coming off an injury-plagued 2019 but ranked in the top 15 in ERA, strikeout rate and ground-ball rate for MLB relievers from 2014 through 2018, according to MLB Trade Rumors, which actually projected in its free-agent rankings that the right-hander will sign a one-year, $5 million contract with Boston.

Kintzler gained some closing experience with the Twins in 2016 and 2017, which could be a consideration for a team lacking a true ninth-inning option. He doesn’t whiff many guys, evidenced by his 6.3 strikeouts per nine innings in 430 career relief appearances, but he posted a fine 2.68 ERA in 57 innings with the Chicago Cubs this past season.

Vizcaino is a wild card, having pitched only four innings for the Atlanta Braves before undergoing season-ending shoulder surgery in April. He throws hard and also has closing experience, though, along with relative youth (he turns 29 on Wednesday).

Again, the list goes on and on, and it seems every season an unheralded hurler (or two, or three…) emerges from the scrap heap to log vital innings. Thus, don’t be surprised if Bloom really thinks outside of the box in building Boston’s bullpen.

After all, the Red Sox already claimed left-hander Josh Osich off waivers from the Chicago White Sox.

Thumbnail photo via Mark J. Rebilas/USA TODAY Sports Images