What can realistically be expected of Giolito?

Lucas Giolito's stock was high when the Nationals selected the Harvard-Westlake High School product with the 16th overall pick in the 2012 First-Year Player Draft.

Giolito's stock has only risen since then, even with the 6-foot-6 right-hander needing Tommy John surgery just a couple of weeks after he was signed.

The 20-year-old is the top pitching prospect in baseball, according to the prospect gurus at MLB.com. He sports a fastball that has reached triple digits in the past, a power curveball and an improving changeup. His potential is through the roof.

All that said, it's important to remember that Giolito has not yet appeared above low Single-A Hagerstown, that he hasn't thrown more than 98 innings in a single season and that he is still on a post-Tommy John plan.

Let's not expect the big right-hander to do too much too soon here.

So what is reasonable for fans to expect from Giolito in 2015, and when could he be ready to make an impact at the big league level?

Well, it appears Giolito is slated to begin the 2015 season at high Single-A Potomac, and he'll get a chance to face some quality talent at that level. Should he continue to progress and build off the strong 2014 season that he put up at Hagerstown (10-2 with a 2.20 ERA and 110 strikeouts in his 98 innings), an appearance at Double-A Harrisburg before the season is up appears likely.

Is it possible that Giolito shows well at Hagerstown and Harrisburg, and ends up becoming an option to slide into the Nationals bullpen late in 2015, giving them a power arm to use for an inning here or there down the stretch? I guess it's possible, and I guess crazier things have happened.

But keep in mind here that the Nationals will still be monitoring Giolito's innings. They won't want their top prospect having to handle too heavy a workload when he only has one full professional season under his belt. Giolito won't turn 21 until July, and he still has some developing to do physically.

More likely, Giolito finishes off the season at Harrisburg (if he keeps progressing and shows he's ready for that level, of course) and then starts the 2016 season at Harrisburg or Triple-A Syracuse, potentially able to move into the Nationals rotation sometime next year or in 2017.

The Nationals will play things by ear with Giolito, letting their scouts' eyes dictate when he gets bumped up to the next level. They know they have a potential top-of-the-rotation starter here, and they don't want to rush him.

Giolito will be taking the mound at Nationals Park soon enough, if he keeps developing and fine-tuning his off-speed pitches. But fans shouldn't get their hopes up about seeing the top pitching prospect in the game in a major league uniform in 2015 or at the start of 2016 just yet.