The Washington Nationals are seeing some fruits of their labor when it comes to their pitching staff.Top prospect Luis Perales is on the big league roster, and although he's not performing well, there is still room for optimism based on his high-end stuff. However, trade deadline acquisition Will Dion has been sensational, and the rookie left-handed duo of Erik Tolman and Jared Simpson have shined during their limited appearances in the majors.That bodes well for what the Nationals will field going forward, especially after years of frustrating results on the mound. But for as exciting as this current crop of arms have been, the next wave offers an even greater potential about what Washington could have on their hands.Landon Harmon Has Ceiling To Be Nationals 'Best Pitching Prospect'Washington Nationals pitcher Landon Harmon | USA TODAY Network via Reuters ConnectThe prospects who Nationals fans and evaluators have circled are Travis Sykora and Jarlin Susana. Ranked No. 2 and 3 in Washington's farm system, respectively, according to MLB Pipeline, that right-handed-pitching duo is considered to be this franchise's two best pitching prospects.However, Keith Law of The Athletic (subscription required) believes there is another player who should be in consideration for that title, as well, as the prominent evaluator had some high praise for right-hander Landon Harmon in his latest scouting report."... this is high-end starter stuff. He might be the Nats' best pitching prospect," he wrote.Law traveled down to see some minor league action in person, and he caught Harmon with Single-A Fredericksburg. Law shared that Harmon sat in the 95-98 mph range with his fastball early in the outing before that ticked down to 91-94 mph during his last inning of work. Fatigue likely played a major part in that, as the youngster appeared to "hit a wall around 50 pitches."Still, Law relayed that Harmon had issues with his command throughout the outing. He walked four batters and "threw a ton of non-competitive pitches," which Law deemed "hard to accept" based on the arsenal that Harmon possesses.Despite all of that, it should be notable for Nationals fans that Law still walked away from that outing saying that Harmon could be the best pitching prospect this organization has. Perhaps that's not too surprising. He got through four innings of work with four strikeouts, no earned runs allowed and just one hit given up in spite of his command issues.An oblique injury has limited the 19-year-old this season to just 11 starts with Fredericksburg. But he's been impressive with a miniscule 1.24 ERA at the Single-A level during his first year of professional baseball. And it's clear that the sky is the limit for him if he can figure out his command.Add us as a preferred source on GoogleFollow