What to expect from Nats' Giolito in big leagues

What to expect from Nats' Giolito in big leagues

With Stephen Strasburg on the 15-day disabled list, the Washington Nationals are calling up right-hander Lucas Giolito to make his Major League debut on Tuesday night at 7:05 p.m. ET against Matt Harvey and the Mets at Nationals Park.

Giolito, MLBPipeline.com's No. 1 overall prospect, is set to make the jump directly to the big leagues from Double-A Harrisburg, where he was 5-3 in 14 starts with a 3.17 ERA and a 72-34 strikeout-to-walk ratio in 71 innings. The 21-year-old allowed two home runs in that span and held opposing hitters to a .247 average.

Giolito has been dominant recently for the Senators, going 5-1 in eight starts from May 9 to June 16. He posted a 1.70 ERA during that stretch, with 52 strikeouts and 16 walks in 47 2/3 innings. Giolito's most recent start was one of his worst of the season, as he allowed five earned runs on seven hits and four walks in 4 2/3 innings on Wednesday, albeit against a talented Portland offense that includes two of the Red Sox's top three prospects in Yoan Moncada (No. 1) and Andrew Benintendi (No. 3).

Baker on Giolito debuting

The Nationals had other hurlers that they could have summoned from the Minor Leagues, such as Triple-A righties A.J. Cole (Nats' No. 7) and Austin Voth (No. 9), but the club instead opted to go with Giolito, its top-ranked prospect, who possesses the highest ceiling and has the greatest impact potential among all Minor League pitchers.

Selected with the 16th overall pick in the 2012 Draft, Giolito missed most of his senior year at Harvard-Westlake (Calif.) High with a sprained ulnar collateral ligament -- an injury which ultimately required Tommy John surgery after he signed. Since then, he's been nothing short of dominant, passing every challenge the Nationals have thrown his way.

After an outstanding full-season debut in the Class A South Atlantic League, Giolito began his 2015 campaign in extended spring training before reporting to Class A Advanced Potomac and, later, Harrisburg. Between the two levels, the 6-foot-6 righty registered a 3.15 ERA and established new career highs in both innings pitched (117) and strikeouts (131). He issued 37 walks and yielded only three home runs on the year. Along the way, Giolito started for the U.S. squad in the 2015 SiriusXM All-Star Futures Game, marking the second straight year he was selected to the event.

From a scouting perspective, there's no better hurler in the Minors than Giolito, who arguably possesses the best fastball and curveball of any pitcher on the current Top 100 Prospects list. He pounds the zone with an elite, 80-grade fastball (on the 20-80 scouting scale, where 50 represents average) that sits mid-to-upper 90s, and opposing hitters have difficulty lifting the pitch due to its consistent downhill plane. The curveball projects to be plus-plus, thrown with 12-to-6 shape and a ton of depth and bite, while his changeup has steadily improved over the past two seasons and should serve as another plus offering for him once fully developed.

But for a pitcher with a lethal fastball-curveball pairing, it might come as a surprise that Giolito has fared better versus left-handed hitters during his career. He's held lefties to a .206/.309/.248 slash line this season, where as same-side hitters are hitting him at a .292/.372/.385 clip.

The Nationals haven't stated whether Giolito will remain with the team once Strasburg, who underwent an MRI for his back injury on Monday, returns from the disabled list. But given Giolito's impressive prospect pedigree and the Nats' diminishing lead over the Mets and Marlins in the National League East, there's reason to believe he'll have the opportunity to prove he belongs in the big leagues.

Fantasy spin | Fred Zinkie (@FredZinkieMLB)
Baseball's top overall prospect per MLB Pipeline, Giolito should be added in all leagues as shallow as 12-team mixed prior to his Tuesday debut. Pitching with Double-A Harrisburg this season, the right-hander has allowed more than two earned runs in just a pair of his 14 starts. But given his inconsistent control (4.3 BB/9 rate in 71 innings this year) and the expected return to health of Strasburg in early July, the 21-year-old should not be taken over Taillon or Blake Snell, youngsters with firm rotation spots.

Mike Rosenbaum is a reporter for MLB.com. Follow him on Twitter at @GoldenSombrero. This story was not subject to the approval of Major League Baseball or its clubs.