SCOTTSDALE, Ariz. -- No pitcher boosted his stock during this Arizona Fall League season more than Brewers left-hander Josh Hader.
Acquired in a trade with the Astros in July as the third-best prospect in the Carlos Gomez for Mike Fiers deal, Hader led the Fall League with a 0.56 ERA and emerged as the top left-handed pitching prospect in the league. He left one final positive impression on Saturday in the championship game, which his Surprise Saguaros lost 6-4 to the Scottsdale Scorpions.
Working the ninth inning in an attempt to keep the game close, he fanned Clint Frazier (Indians) on a sweeping upper-70s slider and Mike Gerber (Tigers) on a 96-mph fastball on the outside corner. A la Madison Bumgarner and Chris Sale, Hader employs a slinging delivery that keeps hitters off-balance and adds life to his pitches, and his fastball has climbed as high as 98 mph this fall. Scouts who cover the league believe Hader has a better chance to make it as big league starter than more famous Fall League southpaws Kyle Freeland (Rockies) and Sean Manaea (Athletics).
Hader was far from the only prospect who distinguished himself on Saturday. Here are six more:
Christian Arroyo, SS, Scottsdale (Giants): As he always seems to do, the 2013 first-round Draft pick made consistent hard contact, collecting two hits and scoring two runs. He also made a dramatic defensive play to end the game, racing from shortstop to make a sliding catch on a foul pop off the bat of Aledmys Diaz (Cardinals). Arroyo probably won't stick at shortstop and he faces an infield logjam in San Francisco, but Arroyo was one of the best pure hitters in the Fall League and his bat will earn him a spot in a big league lineup.
Dustin Fowler, CF, Surprise (Yankees): He began the fall as a taxi-squad player activated only on Wednesdays and Saturdays, but Fowler played his way into full-time status and showed some of the best all-around tools in the league. He concluded his breakout Fall League performance by going 2-for-3 with a walk, including a no-doubt home run off a 97-mph Nick Burdi (Twins) fastball to leadoff the ninth. An 18th-rounder signed for $278,000 in 2013, Fowler has plus speed and center-field skills, solid hitting ability and arm strength, and interesting power potential.
Trevor Hildenberger, RHP, Scottsdale (Twins): Since signing for $1,000 as a fifth-year senior in 2014, he has posted a 1.84 ERA and a 112/12 K/BB ratio in the Minors and put up similar numbers in the Fall League. Hildenberger converted to sidearming as a college junior and throws harder than most pitchers who use that arm slot. Hildenberger worked at 90-93 mph during a perfect fourth inning and also displayed an upper-70s slider.
Dean Kiekhefer, LHP, Surprise (Cardinals): He won't make any top-prospect lists because he's a 36th-round Draft pick who's a low-slot left-hander and purely a reliever. But Kiekhefer throws strike after strike, devastates lefty hitters and could help St. Louis in 2016. He kept the Saguaros in the game with two perfect innings that included a pair of whiffs against right-handers, Adam Brett Walker (Twins) on a sinking changeup and Stuart Turner (Twins) on an upper-80s fastball.
Jake Reed, RHP, Scottsdale (Twins): One of several relievers selected in the early rounds of the 2014 Draft by Minnesota, the fifth-rounder didn't allow a run in 10 Fall League regular-season appearances and struck out the side after a leadoff walk to Gary Sanchez (Yankees) in the eighth. Reed worked at 94-97 mph with his fastball and fanned Patrick Wisdom (Cardinals), Tyler Austin (Yankees) and Bubba Starling (Royals) all on short sliders that climbed into upper 80s.
Mac Williamson, LF, Scottsdale (Giants): Few Arizona Fall Leaguers look the part of a big leaguer more than the 6-foot-5, 240-pound Williamson, who's a good athlete for his size. After missing almost all of 2014 following Tommy John surgery, he bounced back to make his big league debut this September. He worked counts better than most players in the Fall League and delivered a pair of crucial two-strike hits against mid-90s fastballs on Saturday: an RBI triple off Adrian Houser (Brewers) in the fifth and a single to key what proved to be a decisive two-run outburst in the eighth against Jacob Barnes (Brewers), who hadn't allowed a run all fall.
Jim Callis is a reporter for MLB.com. Follow @jimcallisMLB on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.