For a long while there, as Aaron Crow’s career appeared to stall in the minor leagues, and Drew Storen’s took off in the big leagues, the Washington Nationals could feel secure in the knowledge they had gotten the better part of that deal. Remember that deal? It was Crow who, as the ninth overall pick of the 2008 draft, spurned the Nationals’ final offer and chose to go back into the draft — leading to a compensation pick the following year, which the Nationals used to select Storen.

Aaron Crow, the Nationals’ top pick of the 2008 draft, has yet to give up a run in 13 appearances (15 1/3 innings) this season, his first in the big leagues. (Ed Zurga/AP)

But Crow — whose winding path to the big leagues included a stay in the independent American Association, a second trip through the draft (the Kansas City Royals took him 12th overall in 2009) and a rough first year in the minors (a 5.73 ERA in 2010) — made the Royals’ bullpen out of spring training and has been arguably the best reliever in baseball over the season’s first five weeks.

Thirteen appearances and 15 1/3 innings into his big league career, Crow has yet to give up a run (earned or unearned), and he has ascended to the position of top set-up man for closer Joakim Soria, helping the surprising Royals to a 16-14 record. Since 1919, only five pitchers have started their careers with longer scoreless streaks than Crow’s.

“He’s nasty,” said Cleveland Indians Manager Manny Acta, whose team has seen Crow three times already. Acta was the Nationals’ manager in June 2008 when they drafted Crow. “The fastball is 95 to 97 [mph], with a really nice slider. Our guys were coming in [the dugout] saying, ‘This guy is tough.’”

Crow, 24, had never pitched extensively in relief before this season, but between his struggles in 2010 — when he was demoted from Class AA to Class A after 22 starts — and his success out of the Royals’ bullpen this season, the team is at least considering turning Crow into a reliever for good, while saying publicly they still see him as a future starter.

“I still think he has a chance to be a pretty dynamic starter,” Royals Manager Ned Yost told reporters. “We won’t give up on that for awhile.”

Unfairly or not, given the way the Nationals turned the loss of Crow into the addition of Storen, their careers are bound to be measured against each other’s. And who knows? The way things are going in 2011, they may find themselves matched up against each other in the late innings of the All-Star Game.