Justin Williams was drafted by the Arizona Diamondbacks with their second round pick in the 2013 MLB draft, 52nd overall. Williams was extremely young as he was 17 at the time of the draft, but had intriguing raw power.

In the winter of 2014 the Tampa Bay Rays traded Jeremy Hellickson to the Diamondbacks for Williams and Andrew Velazquez. Two very young players that performed well in the low minors.

Heading into the 2017 season Williams ranked number 16 on my personal top 30 list. Baseball America ranked him ninth, MLB.com added him to their top-10, and Eric Longenhagen of Fangraphs.com ranked him 14th. Evaluators agree his defense stands out among minor leaguers, and grades as average should he make the majors, large in part to his great arm. The real question mark has been how his offense will develop.

In the 2017 pre-season Baseball America annual they say, “Williams is a natural left handed hitter with a compact stroke and a knack for barreling the ball. He’s shown an aggressive, if not raw, approach and doesn’t always wait for pitches that he can drive, but he makes as much hard contact as any Rays prospect. His batting practice sessions encourage evaluators that he eventually will develop plus power in games.”

Coming into the season you could see when Williams does get the ball into the air the contact is generally pretty hard and loud. The problem was during his minor league career he had posted groundball rates between 60-65%. That isn’t going to allow your natural power to play.

The second issue was his lack of plate discipline.

In 848 plate appearances during his first two years in the Rays system he picked up a total of 25 walks (2.9% walk rate). His 17.2% strikeout rate isn’t excessive, but it makes it difficult to bring the offensive value you need as a corner outfielder when you’re never walking.

In games last year I saw a hitter that makes Corey Dickerson look like a patient hitter. This led to a lot of weak ground balls due to swinging at bad pitches. It’s a tough profile to work as a hitter without both elite bat to ball skill and power.

The good news was Williams had just turned 20 and had time to improve. He would have to learn some plate discipline to take the next step and if he did he was a candidate to really break out into a potential impact bat.

Last year in time split between A+ and AA Williams hit ten home runs in 358 plate appearances. In his time at Port Charlotte (A+) he put up a great batting average with a minimal 12.8% strikeout rate, but didn’t hit for much power (.119 ISO). His A+ was .330/.350/.448 and a 133 wRC+.

Upon Williams’ promotion to Montgomery (AA) his power started to shine with a .196 ISO in 155 plate appearances. His strikeout rate went back up to 19.4% and his walk rate still hovered around 3% and led to a .250/.277/.446 line and 106 wRC+. His game power was starting to materialize, but the lack of plate discipline could be his fatal flaw that prevents him from being a useful major league player.

2017

Williams got some good looks in spring training, but this year was looking like much of the same through the first month of the season. In 83 plate appearances in April, Williams hit .304/.325/.506. The power continued to appear, but he only walked three times. He still looked like he was swinging at almost everything, maybe he was making better contact. Then on April 30th Williams went on the disabled list with an undisclosed injury that saw him miss about a month of playing time.

Williams returned to Double-A on May 30th, but so did a new approach.

In his next 105 plate appearances through the end of June he started working more counts, but had difficulty maintaining quality contact. He hit .263/.324/.337 and put up a 86 wRC+. He was getting into better counts and picked up ten walks (9.5%) with his strikeout rate (18.1%) remained relatively unchanged, but his power disappeared with a .074 ISO.

Since July 1, Williams has combined the positives and morphed into a monster.

In 190 plate appearances he is hitting .319/.405/.521 and putting up a 166 wRC+. He has earned 26 walks (13.7% walk rate) while only striking out 26 times (13.7% strikeout rate). This is more walks than he received in 848 plate appearances in 2015 and 2016 combined.

Williams looks like a completely different player at the plate. He’s not swinging at everything and he’s making consistent hard contact when a pitcher comes into the zone with a .202 ISO.

Importantly, Williams has improved his batted ball profile. For the first time in his career his groundball rate is south of 55%. Most of the trade off has come in the form of line drives. The next step forward in his development would be getting the ball in the air more frequently.

Justin Williams is a different hitter now

Williams has done just about everything you could hope for to improve his weaknesses. If he’s able to keep up the plate discipline he will realize his upside potential and could be an impact bat.

Willy Adames and Jake Bauers receive all the attention for being young and doing well in AAA, but Williams is only a few weeks older and has taken a massive step towards being a major league regular this year.

MLB.com’s updated prospect list still ranks Justin Williams tenth overall, just ahead of SS Lucius Fox even after the addition of Brendan McKay and Wander Franco to the system, attributing an ETA as early as 2018:

Hit: 50 | Power: 50 | Run: 45 | Arm: 50 | Field: 50 | Overall: 50 Williams began to apply his impressive raw power during games last season en route to a career-high 10 home runs, with six coming in just 39 games at the Double-A level. His approach has also improved, and the left-handed hitter continues to make hard contact across the whole field. A shortstop in high school [...] He's an underrated athlete who moves well and has the tools, including a solid-average arm, to become an adequate corner outfielder. Williams has only started to realize his offensive potential. He's one of several young Rays hitters whose advanced abilities at the plate could get them to the big leagues at a young age.

The Rays have been targeting very young players in most of their recent trades, and that has taken patience on behalf of fans and the organization. The acquisitions of Adames, Bauers, and Williams will start to pay off in the very near future.