Take a half-dozen 19-year-old men without vocal training and ask them to sing the national anthem a cappella and the sound isn’t pretty.

Their pregame serenades at Rocky Miller Park this weekend drew grimaces and suppressed grins from the crowd.

Who was being tortured anyway, the performers or the fans?

Well, it turns out that this unaccompanied ensemble – otherwise known as the freshman class of the Northwestern baseball team – was being subjected to a little rookie hazing.

“They told us back in the fall that we were going to have to sing, but we thought they were kidding around,” outfielder David Gresky said. “We sounded horrible, but we got a few claps.”

This year the tradition was less a cruel punishment and more a playful sign of appreciation, given the immediate contributions of this class.

Emerging from the third week of conference play and the first winning series of the season, NU’s freshmen have been some of the most successful players on coach Paul Stevens’ squad.

Stevens has had to ask a lot of his newcomers following the departure of four starters from last year’s team. And for the most part, his players have wasted no time in overcoming the freshman jitters.

“We lost four or five guys that were fixtures around here for a long time,” Stevens said. “But I’m very comfortable with the Greskys and the (Dan) Pohlmans that are here. Those guys are all very capable of filling shoes.”

Gresky, by far the most vocal of the bellowing ballplayers, has played all three outfield positions and is one of only two players to start each of NU’s 37 games.

At the plate, Gresky has had little trouble adjusting to the college fastball and curveball. The lefty has nestled into Stevens’ lineup in the three-hole and is batting .321.

Gresky’s lone shortcoming is a lack of power, but few of his teammates can complain when NU is averaging about three-fourths of a home run per player.

“There was a lot coming in about how good he was,” freshman pitcher Dan Konecny said of Gresky. “It’s been awesome how he’s proved everyone right. He’s already one of the leaders on the team vocally, and it’s unbelievable how a freshman can do that.”

One of the few players to better Gresky’s average is fellow freshman Jason Krynski. The versatile Krynski, who is listed as an infielder, started in rightfield and on the mound last weekend, serving as his own designated hitter.

In the finale of the weekend series with Indiana, Stevens started three freshman – Gresky in left, Dan Pohlman in right and Josh Lieberman at short.

By the time Konecny and Chuck Sanna entered the game to pitch and pinch hit, respectively, all but one of the team’s freshman had seen action.

But while rookies hold three of the team’s top four batting averages – not counting Andy Adams’ robust 1-for-2 – Stevens has had to deal with a steep learning curve on defense.

This season the Cats have already made three more errors than they made all last year, and there are 16 games left on the schedule. The freshmen account for 23 of NU’s conference-leading 80 miscues. Stevens, however, said he is confident the errors will dwindle with experience.

This weekend alone, the improving infield turned eight double plays against Indiana.

If the defense gets smoothed out and the freshmen can combine a clean pick in the hole with a timely pinch hit, NU should be in position to contend for more than just the conference’s last tournament seed.

“I came in with the intent of going for a year or two without much playing time,” Krynski said. “But coach puts a lot of trust in us. And it’s only going to look (better) in a couple of more years.”