OAKLAND -- A tough-luck injury prevented Jorge Mateo from reaching the Majors in 2019, but his overall body of work has positioned him nicely as one of the A’s top hitting prospects.

Mateo has been named Oakland's Minor League Hitter of the Year by MLB Pipeline, while right-hander Daulton Jefferies earned top pitching honors. In a year when many of the club’s top prospects were called up to contribute to a playoff race, these two prospects could be next in line to make an impact in 2020.

The 24-year-old Mateo bounced back from a disappointing 2018, his first season at Triple-A, by going on a tear that led to his selection to the Pacific Coast League All-Star team as he established himself as one of the top infield prospects in the Minors.

Mateo, Oakland’s No. 4 prospect, was long known as a speedster; he stole 82 bases in 2015 while playing in the Yankees organization. But what stood out this season were his overall numbers at the plate. Mateo slashed .289/.330/.504 with 19 home runs and 78 RBIs over 119 games for Las Vegas. He led the Pacific Coast League with 14 triples and led his team with 24 swipes.

Mateo was looking like a surefire bet to reach the Majors as a September callup, but he was pulled from a game in the PCL playoffs after getting hit by a pitch on his right hand, essentially ending his season.

Marcus Semien has the shortstop position on lock after a breakout season both at the plate and on defense this year, but Mateo could be an option for the A’s at second base. Jurickson Profar appears to be transitioning into more of a utility role, leaving a hole at the position that Oakland could look to fill internally with Mateo, Franklin Barreto and No. 8 prospect Sheldon Neuse, who is already contributing in the Majors this September, as options.

Jefferies, the A's No. 12 prospect, earned Oakland’s Minor League Pitcher of the Year Award after working his way back from 2017 Tommy John surgery. After rehabbing caused him to miss most of '18, the 24-year-old is back on the radar as the promising arm the A’s expected when selecting him in the first round of the '16 MLB Draft.

Jefferies went 2-2 with a 3.42 ERA, starting the year at Class A Advanced Stockton and finishing up with Double-A Midland. In an effort to limit his innings as he returns from Tommy John, Jefferies worked three innings or fewer in 24 of his 26 outings.

In an effort to integrate a breaking ball into his arsenal, Jefferies worked with A's Minor League pitching coordinator Gil Patterson to develop a cutter. The pitch produced good results, but then Jefferies decided to tweak the pitch later in the year and transformed the cutter into what Patterson described as a "sweepier curveball/slider mix" that led to higher swing-and-miss rates.

"Him being able to pitch this year and go to 80 innings after the adversity he's been through, [it] speaks volumes," Patterson said. "His fastball and changeup have always been good. It was a slow process because he's been injured, but this year we basically started off with a cutter. His transformation of throwing the cutter and making it bigger and sweepier was a great help to his development.

"It's really him. I'm never going to tell you pitching coaches don't tweak pitches here and there. But his work ethic and attention to detail is tremendous." 

Possessing a 95-mph fastball to go with a strong 89-mph changeup, Jefferies racked up 93 strikeouts over 79 innings. He also displayed supreme control of his pitches, issuing just nine walks. Jefferies will be an intriguing option as he returns to action in 2020 with fewer restrictions, as yet another starting pitcher with high expectations in the A's farm system.

"When you look at those walk numbers, I know it's in the Minor Leagues, but I don't care who you are," Patterson said. "You look at [Roger] Clemens or [Randy] Johnson, [Max] Scherzer, and you see if they ever did that in the Minor Leagues, my guess would be no. What he did this year was quite impressive."