PORT ST. LUCIE, Fla. -- Toward the end of last summer, Mets manager of baseball research and development T.J. Barra approached Paul Sewald with a suggestion. Though the reliever was enjoying a fine year overall, establishing himself as the closer at his hometown park in Triple-A Las Vegas, he posted a 5.28 ERA over a five-week span from late May through the end of July. Barra offered a solution, presenting Sewald with data suggesting he should throw his best pitch, his slider, more frequently.

Digesting that immediately, Sewald went his final seven appearances without allowing a run. He finished the year with a 3.29 ERA in the hitter-friendly Pacific Coast League, collecting 80 strikeouts in 65 2/3 innings. It was enough to bump Sewald up to 10th among all Double-A and Triple-A pitchers in strikeout-to-walk ratio since the start of 2015, and 14th in overall strikeout rate.

Sewald is now trying to parlay that success into an Opening Day roster spot. With several members of the 2016 bullpen off to poor starts, Sewald, submariner Ben Rowen, and lefties Josh Smoker and Adam Wilk have emerged as the Mets' most promising relief candidates in camp.

"I'm still in camp," Sewald said on the morning of the Mets' first cuts. "They're still throwing me out there every third day, which means I'm here and I'm trying to fight for a spot like everybody else."

Buzzing through two perfect innings in a 6-0 loss Saturday against the Nationals, Sewald did nothing but help his cause, reducing his Grapefruit League ERA to 1.29. His lone strikeout came on a 91-mph two-seam fastball that he guided over the plate's inside corner. The right-hander also relied heavily on his slider, which he threw as soft as 80 mph and as hard as the mid-80s. And Sewald is working on a changeup, which he estimates he's already thrown more this spring than all of last season.

Following Sewald's first Grapefruit League outing last month, Barra presented him with another sheet of paper filled with information from First Data Field's Trackman system.

"It blew me away," Sewald said. "When you look on a piece of paper and it says, 'This is what they do against your slider. This is what they do against your fastball,' it's, like, 'Whoa. Nobody hits my slider.'"

For Sewald, that does not necessarily mean throwing his best pitch as often as possible. It means throwing it more often, to be sure, but also picking spots when history has proven it most effective.

If Sewald can continue learning that, his path to the Opening Day bullpen will become that much clearer.

"He's a strike-thrower," manager Terry Collins said. "Ultimately, when we get down toward the end, when we decide where we stand with our bullpen … he might be in that mix."

Considering the quality of Sewald's 2016 season, it seemed possible the 26-year-old would arrive at Citi Field even sooner, as a September call-up for the playoff push. That didn't happen, keeping a "disappointed" Sewald off the 40-man roster -- a disadvantage for him now as he tries to make the team.

But success speaks, and Sewald is using all the information at his disposal to continue it.

"I might not be throwing 100, but I feel like I have pretty good stuff and I just use it to my advantage," Sewald said. "So that's kind of how I go about it. I'm not going to worry because I don't throw 100 and I'm never going to throw 100, and at that point, there's nothing I can do other than be the best that Paul Sewald can be."

Anthony DiComo has covered the Mets for MLB.com since 2008. Follow him on Twitter @AnthonyDiComo and Facebook, and listen to his podcast.