There is certain undeniable artistic flair to how a general manager constructs a bullpen. It’s a work of art that is constantly in flux. Often times relievers materialize out of thin air off the waiver wire or free agency mid-season. They arrive as complementary pieces in much larger trades. Others are the result of a failed experiment in the starting rotation. There is no set formula for assembling a successful bullpen, which is why it’s strange that a small handful of general managers have been able to consistently put them together top-notch pens, while the rest of the league flounders in a wasteland of mediocrity.

Since 2010, Atlanta and San Diego are the only teams to finish top-10 in bullpen ERA every season. Two very distinct forces of nature, Craig Kimbrel and PETCO Park, might have a little something to do with that for both organizations. The only club that has come close to matching their success during that span are the Oakland Athletics, who have ranked fourth, sixth and third in bullpen ERA over the last three years.

Relievers, especially middle relievers are the most fungible assets in the game. That’s no secret. It’s not like Billy Beane needs any more publicity, but it is worth noting that one area in which he has lapped the competition is in how he has gone about constructing his bullpen in recent seasons. It fits a cliche “Moneyball” narrative, but he literally has constructed an elite bullpen out of castaways, set adrift by other organizations, which have cost him next to nothing to acquire.

Jesse Chavez pitched for the Pirates, Braves, Royals and Blue Jays before the A’s snagged him in 2012. Since that time, he’s evolved into one of the most valuable swingmen in the game and has pitched well enough to stay in the rotation full-time for the remainder of the current campaign.

Fernando Abad washed out with the Astros and Nationals before settling in as an integral left-handed weapon for Bob Melvin last year. Fellow southpaw Eric O’Flaherty was picked up off the scrap heap last summer and ended up posting an impressive 2.25 ERA in 21 appearances. Dan Otero was waived by both the Giants and Yankees before returning to the Bay Area back in 2013. In the two seasons since he posted ERA’s of 1.38 and 2.28, respectively.

Sean Doolittle might be the most compelling success story of the entire bunch, transforming from failed minor league first baseman into dominant closer in less than three years. The lone acquisitions, which have cost Beane any resources to acquire, Tyler Clippard and Luke Gregerson (who signed with Houston as a free agent this past offseason), were widely considered among the most undervalued relievers in the game prior to the deals that brought them in. Clippard has thrown more innings (393.1) than any reliever in the game since 2010, while Gregerson has eclipsed 65-innings in all but one season dating back to 2009.

You can make the argument that not all of the acquisitions panned out. The most notable exception is big-ticket free agent Jim Johnson, who didn’t even last a week before he was replaced as the teams closer last year. Overall, Beane has done a fantastic job turning other teams “trash” into the A’s bullpen treasure.

One of those under the radar finds, Evan Scribner, who was claimed off waivers from San Diego back in 2011, has not only emerged out of nowhere to become a key member of the A’s bullpen, but he ranks among the most valuable relievers in the game this season.

Scribner has never thrown more than 35 innings in a single season since 2012. The Connecticut native has spent much of his career as the prototypical “25th man” on Oakland’s roster, shuffling between Triple-A and the Majors whenever they needed an extra arm in the pen. This season has been a different story as he’s tossed more innings (26) than all but five relievers in the game. More impressively, he ranks ninth in strikeouts with 29 punch outs.

He’s always had the control and command as evidenced by a 1.98 BB/9 rate for his career. However, with his strikeout rate surging (career-high 10.04 K/9), and a minuscule walk rate (0.69 BB/9) remaining intact this season, Scribner has elevated his game to another stratosphere.

It may be a generalization, but it would seem to be a logically sound conclusion that generating weak contact leads to fewer hits. Scribner has posted the best rates of his entire career in the contact department according to Baseball Info Solutions data compiled on FanGraphs. He’s inducing more soft contact (20.9%) and less medium contact (49.3%) than ever before, which has offset a slight uptick in hard contact (29.9%). He’s also on track to post a higher ground ball than fly ball percentage for the first time in his career. Simply put more groundballs and softer contact is a huge step forward for Scribner and backs up his early season results.

Another noticeable change for Scribner is that he’s throwing harder than he ever has in the past. His average fastball velocity is up over 92 mph this season, which represents a new career-high.

Opposing hitters are also batting a paltry .194 against his fastball, which is a far cry from the .375 average opponents racked up against his heater last season.

Scribner is also leaning more on a new mid-80’s mph mystery offering on nearly 25% of his pitches this season. PITCHf/x and Brooks Baseball classify it as a slider. A’s manager Bob Melvin has referred to it as a cutter. Regardless, the pitch has some movement to it and the change in speed has given Scribner something else in his arsenal to split the difference between his trademark fastball and mid-70’s mph curveball mix.

If this is the new Scribner, a three-pitch right-hander, capable of racking up prodigious strikeout totals in low-leverage situations, he becomes one of the more intriguing relief pitchers in the game from a fantasy perspective. Given the presence of both Clippard and Doolittle, he may never get a shot to close, but his ascension from the A’s roster bubble to an integral late-inning option is worth taking notice of in deeper dynasty formats.

You can follow George Bissell on Twitter @GeorgeBissell