Practice isn't over until the fullback sings

So, people ask Harvard's fullback/tenor, is there any connection between football and opera? "Incredibly so," nods Noah Van Niel, who handles defensive linemen and Donizetti with equal aplomb. "It's rehearsing a set of skills and then going out and performing. There's pressure and there's an audience and there's nerves: Can I do this?"

There are also playbooks, and while Harvard football's is undeniably thicker and more complex, the operatic version comes in four languages - English, Italian, German, and French. "You've got to know them like the back of your hand," says Van Niel, who has taken two years of college Italian.

And later this fall, when Van Niel is auditioning for postgraduate programs in vocal performance, he'll have to know Dies Bildnis from Mozart's Magic Flute and four other arias by heart. "It's just like football," Van Niel says. "When they call a play for you on the goal line, you can't say, 'I don't know that one.' "

So after football practice at the Stadium, the curly-haired, barrel-chested Newton native walks back across the Larz Anderson Bridge to Dunster House, his riverside dorm with the crimson dome, locks himself inside a practice room, and has at Signor Donizetti for an hour.

"Noah takes his singing as seriously as his football - if that's possible," says Sharon Daniels, the director of opera programs at Boston University's Opera Institute, who has taught Van Niel since he was a junior in high school.

Football all but certainly will end for him on the Saturday before Thanksgiving as dusk is falling in New Haven, where Harvard will play archrival Yale. "It would be an honor to play in the NFL, but I don't think that would ever happen," he says. "I think I'm destined to end my career in Yale Bowl on Nov. 17. I've gotten four more years than most people get."

Meanwhile, his opera career is on the upswing. After summer apprenticeships in Florence and New York, Van Niel is ready to take it up an octave. He wouldn't be the first Harvard ballcarrier to exchange a uniform for a costume. Ray Hornblower, a star halfback on the unbeaten 1968 team, is a superb lyric tenor who has performed throughout Europe. "I met Ray in New York last summer," says Van Niel. "It's sort of fun to know I'm not the first."

Van Niel began singing semi-seriously just before puberty, in church and summer camps, then in musical theater and operettas in middle school and high school. But it didn't take long for Daniels, who didn't teach high schoolers as a matter of policy, to see the passion and promise there and make an exception. "Noah just came to me so eager and so talented," she says.

His breakout came in college, when he spent three weeks in the Florence Voice Seminar. "That was the experience of a lifetime," says Van Niel, who lived within walking distance of the Duomo and the Ponte Vecchio.

What he discovered during his Tuscan sojourn was that he knew his way around an aria. "I saw that I was competing pretty well, and that inspired me," he says.

Last summer, Van Niel did full immersion at the Martina Arroyo Prelude to Performance program in Manhattan, where he spent the day attending opera workshops, studying librettos and recitatives, and learning about staging, and then headed to Central Park to do his football workouts. "I'm sure I scared some people," he says. "They'd see this 250-pound guy running wind sprints, looking like he was about to collapse."

It was there that Van Niel concluded he had what it takes to stay in the operatic game. "I wasn't out of my league," he says. "I was just sort of like a rookie. Now that I know what's out there, how do I become what's out there - and more?"

What's next is either an opera school or a professional training program, probably near New York, and the continuation of his vocal apprenticeship. "I'm still very much a baby by opera standards," Van Niel says. "If you're singing at the Met in your late 20s, that's pretty amazing. It usually doesn't go like that."

His football apprenticeship at Harvard lasted for three years, until tailback Clifton Dawson, the best runner in school history, moved on and up to the Colts and Van Niel finally got to carry the ball. Last weekend, he scored the first two touchdowns of his career against Lafayette - one running, one receiving. "We feature him because he deserves it," says Crimson coach Tim Murphy, who uses Van Niel in short-yardage and goal-line situations and as an occasional receiver.

Van Niel had been an eclectic athlete at Newton North High School, captaining the football and lacrosse teams and making All-State as a swimmer after starring as a youth soccer goalie. (His father, Anthony, played soccer at Harvard in the early 1970s.) But his blockish build tilted him toward the gridiron. "I couldn't play Pop Warner because I was too big," Van Niel says. " 'Mom, ' I said one day, 'I'm sort of meant to play football.' "

And Harvard, literally just down the Pike, figured to be the spot. "This is the place where football was invented," he says.

Though he's dreading the day when he pulls off the jersey for the final time, dropping football from his "to-do" list undeniably will make life simpler. It'll give Van Niel more time to bone up on his other playbook, the five arias he'll need for his auditions. "They're known as The Five," he says. "Someone will ask, 'What are your five?' "

Van Niel's five are "Dies Bildnis," "Una Furtiva Lagrima" from Donizetti's "Elixir of Love," "Ecco, ridente in Cielo" from Rossini's "Barber of Seville," "Ah, Mes Amis . . . Pour Mon Ame" from Donizetti's "La Fille du Regiment," and the Aria of the Italian Singer from Strauss's Der Rosenkavalier.

Van Niel not only has to know the arias note for note, he has to pronounce the words correctly - and feel them. "I need to have my French, German, and Italian singable and discernible for the audience," he says.

In opera, like football, it's all about execution, and even the best of them get butterflies. "The reason why Luciano Pavarotti would hold that handkerchief was because his hands were shaking," Van Niel says.

He hasn't yet performed at the Met or La Scala, but the man has worked his craft in front of more than 30,000 spectators inside a stadium modeled after a Roman colosseum and a Greek amphitheater. Next month, Van Niel will suit up for his finale at the Bowl, then walk off one stage and onto another.

John Powers can be reached at jpowers@globe.com.