WASHINGTON -- Last summer, the Nationals saw the rival Mets promote two top pitching prospects -- Noah Syndergaard and Steven Matz -- to bolster their rotation en route to a division title and National League pennant. Now the Nationals have their own top pitching prospect that they are ready to insert into their rotation and into the heart of a divisional battle tonight.
Right-hander Lucas Giolito, the No. 1 prospect in baseball according to MLB Pipeline, will make his Major League debut in the 7:05 p.m. ET game at Nationals Park against the Mets and right-hander Matt Harvey. He was called up from Double-A Harrisburg, where he was 5-3 with a 3.17 ERA in 14 starts.
Giolito will make the start in place of right-hander Stephen Strasburg, who was placed on the disabled list Sunday with an upper back strain, with a chance to widen Washington's four-game lead over New York after winning the series opener, 11-4, on Monday. Whether Giolito remains in the Majors for the long haul remains to be seen, however. Nationals general manager Mike Rizzo said the club will take it start by start.
"We figured he gave us the best option to win the game tomorrow," Rizzo said. "He's our No. 1 prospect. We like the way he's developed. We think he'll do well and give us a chance to win."

Giolito joins a number of heralded pitching prospects to make their debuts this season, including Dodgers left-hander Julio Urias and Pirates right-hander Jameson Taillon -- both of whom also faced the Mets in their first starts. On May 27 in New York, Urias -- Pipeline's No. 2 prospect -- allowed three runs on five hits in 2 2/3 innings, walking four and striking out three in a 6-5 Mets win. Pitching at home on June 8, Taillon, ranked 49th, allowed three runs on six hits in six innings, walking two and striking out three in another 6-5 Mets victory.
Washington is no stranger to debuts for highly anticipated pitching prospects, including Strasburg's own unveiling in June 2010. The No. 1 overall pick in 2009, Strasburg wowed from the start, striking out 14 Pirates in seven innings, allowing two runs on four hits with no walks. He got the win in the Nationals' 5-2 victory.
Rizzo said he was trying to "calm down the hype a little bit" for Giolito's debut, which will be easier said than done.
Giolito, 21, has struck out 72 in 71 innings at Harrisburg. Rizzo revealed that the Nats were getting ready to promote Giolito to Triple-A soon before Strasburg landed on the DL.
• What to expect from Giolito in the big leagues
MLB Pipeline's scouting report on Giolito says he has the stuff to develop into an ace with "the highest ceiling among Minor League pitchers, boasting an elite fastball that sits mid-to-upper-90s and a 12-to-6 curveball that he throws with power and hard, downer action. His changeup has steadily improved in the past two seasons and his confidence along with it, giving him a legitimate weapon against left-handed hitters."
Giolito throws harder and from a closer distance to the plate than most pitchers, giving hitters a limited time to react. Statcast™ data from the 2015 Futures Game in Cincinnati measured that Giolito allowed hitters just .38 seconds from the time the ball leaves his hand until it reaches the plate, matching flamethrowers like Syndergaard, Dellin Betances, Craig Kimbrel and just behind Aroldis Chapman.

And Giolito's debut will come in a crucial game against a division rival that the Nationals will almost certainly compete with for the NL East through the remainder of the season.
"He's not feeling the hype," Rizzo said. "It's not going to be another day at the office for him because there's going to be a second deck on the stadium that he pitches in this time, but he's a confident kid that I think will handle the pressure of his Major League debut against a really good team like the New York Mets in stride and give us a chance to win the baseball game."

Giolito's ascent to the Majors has been swift since he was drafted by the Nationals in the first round (16th overall) of the 2012 MLB Draft. He had Tommy John surgery shortly after signing and did not make his full season debut until 2014.
• Cut4: 5 things to know about Giolito
And Rizzo said Giolito will be able to pitch without any innings restrictions, either for his start Tuesday night or limits for the rest of the season. Whether those innings are for the Nationals remains to be seen.
"He's always been a professional attitude type of player, even as a young Minor Leaguer," Rizzo said. "He's very poised and confident. A guy with great stuff. He works extremely hard in preparation for his starts, physically and game preparation. So I don't think that he'll be overwhelmed in the situation. He's a guy, with his makeup and confidence level, we feel good about."
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.