Editor's Note: Two weeks ago, we introduced Paul Mammino's work on relievers based around xADREIP, a stat that helps identify upside and downside, along with sleepers and busts among relievers. To see the full results of Paul's research, go to SportsLine.com now.

As spring training opens there are several position battles worth monitoring for Fantasy purposes, but none are as important to Fantasy players as the closer battles. Below are some of the current battles using my reliever model to compare the options and to predict who is the one to own in 2019.

Tier 1

Boston Red Sox: Matt Barnes vs. Ryan Brasier


The Red Sox fall into a tier entirely of their own because they are easily the best projected team to enter the spring without a set closer. At any point they could always bring back Craig Kimbrel, making this all moot, but for the moment we have the veteran Barnes versus the pop-up 31-year-old rookie in Brasier.

Looking at the chart above, it is obvious that Brasier is the preferred option as his probability of reaching the more valuable tiers is higher across the board than Barnes. The issue here is the sample size: Brasier only has 2018 and a small sample of 2014 for us to work with, and the excellent control he showed in 2018 does not exactly line up with his minor-league results. The interesting thing is his near elite swinging strike rates — 15th among relievers with over 30 innings in 2018 — do not match up with an elite K/9. If he can convert more of his swings and misses into Ks, then Brasier should be able to thrive in the role. The Red Sox should give him every chance to seize the job, and he is the one Fantasy owners should be investing in. Winner: Brasier

Tier 2

Philadelphia Phillies: David Robertson vs. Seranthony Dominguez


While not projected to be quite as good as the Red Sox, the Phillies do project to be a wild-card contender. They jumped on the reliever market early this offseason, signing the ever-consistent Robertson to compete with budding star Dominguez. Robertson has been one of the most consistent relievers in the game, throwing over 60 innings every year since 2010 and posting K/9 rates over 10 every season within that span as well.

In his 58-inning debut, Dominguez showed elite swing and miss skill and displayed the profile of a future star. Looking at the chart above, it appears Dominguez has a higher chance of reaching the elite tiers, while Robertson has the best chance of an average season; the two are similar in their chances of a below average season. Due to his remarkable consistency, I expect the Phillies to open the season with Robertson as their closer and Dominguez in a fireman, Josh Hader-type role. That still carries significant value, but for Fantasy purposes I would predict that Robertson is the one to own. Winner: Robertson

Milwaukee Brewers: Josh Hader vs. Corey Knebel vs. Jeremy Jeffress


Last season was an interesting for the Brewers bullpen, as Corey Knebel was coming off an elite 2017 and struggled out of the gate before getting hurt. The job was then passed along to Hader, who excelled as he did in pretty much every appearance in 2018, posting gaudy strikeout numbers and making hitters look lost. Then Jeffress, a former Brewers closer, stepped in and finished the season with the job.

Upon returning from injury and a demotion, Knebel was nearly unhittable down the stretch and took the job back from Jeffress during the postseason when Jeffress struggled mightily. So, heading into 2019, there are several questions on exactly who will take over. The chart unsurprisingly likes Hader to have the most upside with all three guys close in the middle portion, and Knebel showing the highest downside. This metric is wary of Knebel's control issues.

However, I do not believe this chart takes the whole picture into account. Hader will likely remain in a fireman role and is unlikely to be the full-time traditional closer barring some major collapse from the other two. While it is an admittedly small sample, Knebel was elite in September/October and only had three walks in 16 innings while maintaining his incredible K rates. The control improvements carried into 10 playoffs innings. If he can continue the growth in this area, Knebel could return to the elite promise he showed in 2017. He is the one to bet on for Fantasy purposes. Winner: Knebel

Minnesota Twins: Trevor May vs. Blake Parker


Both guys have taken interesting paths to get here. May was once a well-regarded starter prospect who dealt with injuries, including Tommy John, missing all of 2017 and returning to only throw 25 MLB innings in 2018. Those innings were solely out of the pen and they were electric. He had some homer issues, but as a full-time reliever, May posted a minuscule walk rate coupled with a top-20 swinging strike rate.

Parker seemed to always be a closer in waiting but was left perpetually waiting behind Huston Street as Mike Scioscia repeatedly let the aging closer work the ninth despite regressing numbers. Parker was finally given the job in 2018, but struggled compared to the promise he had previously shown. When Parker signed with the Twins this offseason, many believed that he was going to take over the job as a veteran with "experience." However, it appears May and others (Taylor Rodgers and Fernando Romero) will get a chance to compete.

As the chart shows, Parker is the lesser of the two options and has significant downside, most of which can be shown by his 2018 season. If he can see a slight return to his 2017 K rates, maybe Parker can bounce back to the future stud closer many were predicting him to be. Based off 2018, May should get every chance to get the job in 2019. However, be cautious because according to Baseball-Reference, May only pitched on no-days rest twice in 2018. If the Twins are going to use him as a closer, they will need to see if his stuff and arm can hold up to pitching multiple days in a row. If he can, he could be an elite investment for Fantasy owners at his current ADP. Winner: May

Atlanta Braves: Arodys Vizcaino vs. A.J. Minter


I will admit when I first looked at this comparison I did not expect the chart to come out like it did. I expected to leave liking Minter much more than I do now. He was a trendy sleeper last season coming off an incredibly small sample in 2017. In 15 innings the lefty posted a 15 K/9 and a BB/9 of just over 1. Many believed he was going to take over for Vizcaino and run with the job. Minter did end up getting 15 saves mostly due to an injury to Vizcaino, who actually ended up outperforming Minter. 

Minter's insane K numbers regressed slightly, and his walks increased as well. In the end he ended up looking a lot like Vizcaino. The one thing Minter has done better than his right-handed counterpart is limit the long ball. Vizcaino has been a bit homer prone the past two seasons while Minter has been able to suppress them. 

The chart views Minter as a higher-upside, higher-risk option, and Vizcaino more as a you-get-what-you-see option — a perfectly average, unspectacular reliever. Going into 2019, I would expect this job to remain with the right-handed Vizcaino and his steady production. Teams typically prefer the guy with "experience" over the alternative, and typically prefer a right-hander to a left-hander. Minter does not have any major platoon issues, but history tell us that this tends to be the case. However, if Vizcaino falters, Minter will be extremely capable of picking up the pieces as he showed last season. Winner: Vizcaino