Nats believe Giolito gives them "best option to win" Tuesday

The Nationals had seen enough of Lucas Giolito in recent weeks to believe he was ready for a promotion. To Triple-A Syracuse, not the big leagues.

But when Stephen Strasburg's lingering back injury opened up a spot in their rotation, the Nationals decided to go ahead and promote their top pitching prospect all the way up from Double-A Harrisburg and send him to the mound Tuesday night against the Mets.

"We figured he gave us the best option to win the game tomorrow," general manager Mike 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, 21, has been regarded one of baseball's best prospects since the Nationals selected him 16th overall in the 2012 First-Year Player Draft out of his Los Angeles area high school. Even with a year off while recovering from Tommy John surgery - which the organization knew he was going to need at the time of the draft - the right-hander has sped his way through the system, advancing from rookie ball to Double-A in roughly two calendar years.

This final step is the biggest, of course, but the Nationals have long believed Giolito has not only the pitching repertoire but also the makeup to make the leap.

"He's very poised and confident," Rizzo said. "A guy with great stuff. He works extremely hard - 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."

Giolito's numbers at Harrisburg - 5-3, 3.17 ERA, 105 baserunners in 71 innings - weren't head-turners. But after a shaky start to his season, he turned a corner in the last month, posting a 1.45 ERA and 39-to-8 strikeout-to-walk ratio over a stretch of five recent starts before a rough outing his last time on the mound.

The current Nationals coaching staff got a good sense of Giolito this spring in his first big league camp. Included in that stint was a start against the Mets in Port St. Lucie on March 18, when Giolito tossed two scoreless innings on 26 pitches vs. an "A" lineup that included Curtis Granderson, David Wright, Yoenis Cespedes and Lucas Duda.

"You don't know if he's ready or not until they actually get here and perform," manager Dusty Baker said. "And then you still don't know if they're ready because it takes a while for the league to learn you and you to learn the league. But I liked what we saw in spring training."

Neither Rizzo nor Baker would commit to anything for Giolito beyond Tuesday night's debut, which happens to come against New York's Matt Harvey, but it's possible Strasburg will miss more than this start before returning from the disabled list. The ace right-hander had an MRI this morning to determine what, if anything, is going on in his upper back that caused enough discomfort to force him to be scratched from two scheduled starts in the last week.

After throwing a total of 117 innings last season, Giolito figures to be restricted roughly to 150-to-160 this year, based on the Nationals' typical protocols for young pitchers who had Tommy John surgery. His current total is 71, but Rizzo claimed that's not a factor at the moment.

Asked if there are any limits on his young starter either Tuesday night or long-term, the GM replied: "No, he's not on any type of limit at all."