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8/13/2014 10:00 A.M. ET

Pipeline Perspectives: Giolito has best raw talent

Mariners' Walker is more proven, but Nats right-hander will be a better big leaguer

There's a good amount of subjectivity regarding baseball prospects. With the evaluation of talent being in the eye of the beholder, finding consensus is often difficult. Even Jim Callis and Jonathan Mayo of MLBPipeline.com don't always see eye to eye. They discuss their viewpoints regularly in a feature called Pipeline Perspectives. Submit a topic for them to debate.

For the first couple of months in 2012, Lucas Giolito looked poised to make First-Year Player Draft history.

After hitting 100 mph during the offseason and regularly reaching 99 mph during the early portion of Harvard-Westlake School's (Studio City, Calif.) season, Giolito was positioning himself to become the first high school right-hander taken with the Draft's No. 1 overall pick. That possibility got derailed, however, when he sprained the ulnar collateral ligament in his right elbow in early March.

Giolito didn't return to the mound before the Draft, and teams were concerned about both his asking price and the likelihood that he would need Tommy John surgery. Undaunted, the Nationals selected him 16th overall and paid him $2.925 million to pass up a scholarship from UCLA.

Washington didn't get much of an initial return on its investment. Giolito made one two-inning appearance in pro ball before having his elbow reconstructed, and he worked just 36 2/3 innings in 2013 as the Nats brought him back slowly. But with the way he has progressed this year, the club has absolutely no regrets.

Giolito didn't turn 20 until the day after pitching in the SiriusXM All-Star Futures Game, and he has yet to pitch above low Class A. Even with a relatively limited résumé, he has shown enough to earn acclaim as the best pitching prospect in baseball.

Jonathan Mayo may not agree, identifying Mariners righty Taijuan Walker as the best pitching prospect, but multiple scouts say Giolito has the best pure stuff in the Minor Leagues.

It starts with Giolito's spectacular four-seam fastball. The first three pitches he threw when he got back on the mound in a game in 2013 were clocked at 100 mph. Giolito doesn't feel the need to light up radar guns every time out, and he has spent most of this season pitching at 93-96 mph while expending little effort.

As if his velocity weren't enough, Giolito's fastball plays up because of its life and plane. He can run his fastball to either side of the plate, and his 6-foot-6 frame allows him to throw it on an extreme downhill angle.

Hitters can't afford to try to gear up for Giolito's fastball because his curveball can be nearly as nasty. It may lack consistency at times, but at its best, his curve is a true 12-to-6 breaker that can reach the mid-80s. Giolito also has nice feel for his sinking changeup, which shows flashes of becoming a plus pitch.

When all is said and done, Giolito could have an 80 fastball, a 70 curveball and a 60 changeup on the 20-80 scouting scale. The Nationals haven't allowed him to throw any two-seam fastballs yet, so that's an additional weapon he'll probably add at higher levels.

Giolito is committed to developing his entire repertoire, as evidenced by his most recent start on Monday. He decided to shelve his curveball to focus on commanding his fastball and changeup, and he wound up striking out six in five scoreless innings.

Giolito has translated his stuff into superlative performance against low Class A hitters this season. If he weren't currently four innings shy of qualifying for leadership -- he comes up short because the Nats had him skip three starts in May to keep his workload down -- he would top the South Atlantic League in strikeouts per nine innings (10.2), baserunners per nine innings (8.9), opponent batting average (.188) and ranks a close second in ERA (2.23).

Walker has proven more than Giolito to this point, already having made six starts in the big leagues. At the same age Giolito is now, Walker already was in Double-A because he hadn't lost a year and a half to Tommy John surgery.

Giolito has a better fastball and a better breaking ball than Walker, and he has more advanced control and command than Walker did at the same stage. In the long run, Giolito will be a better big leaguer than Walker, and better than any other pitching prospect currently in the Minors.