When Mozart revised “Messiah” in the 1780s, he was taken to task for writing parts for approximately 30 performers, a larger ensemble than had been employed by Handel. In the next century, up to 3,000 participated in performances at the Crystal Palace in London. Like most modern groups, the New York Philharmonic weighs in somewhere in the middle.

The instrumental forces employed by the Philharmonic on Wednesday evening were what would be called a “split squad” in baseball spring training. Many players stayed home at Avery Fisher Hall to play a concert led by Christian Zacharias, while others got on a bus and traveled to play a scrimmage with the Devil Rays.This perplexing band often sounds considerably better when they are not all together, and that was certainly the case during the Phil’s performance of the “Messiah” at the Riverside Church.

The Phil hired a true expert for Messiah. Richard Hickox is the founder of both the City of London Sinfonia and the Collegium Musicum 90 ensemble. He led what can only be described as a British version of the piece – restrained if you liked it, constricted if you did not. The instrumentalists played close to flawlessly, making a joyful noise augmented by the harpsichord of Lionel Party, but they never were encouraged to let loose or explore the inherent power of the music. What should have been insistent rumblings were but ripples in a pool.

Riverside is shaped like a cathedral and was constructed on a grand scale, but it is remarkably devoid of echo effect, offering instead a forthright and accurate instrumental sound. Principal associate concertmaster Sheryl Staples performed admirably as a role model to a smallish group of strings with but a few wind and brass players. (I didn’t stop to count the musicians, but you can extrapolate from the total of only two double basses.) Both Ms. Staples and Glenn Dicterow are relatively young, and I hope that she isn’t simply waiting for him to retire. She can play rings around several other highly touted leaders in the United States, but that pesky New York Philharmonic salary might keep her indentured for far too long. Of course, I wouldn’t move out of town for any other job, either.

The Westminster Symphonic Choir delivered its standard muddy realization with suspect diction, even in English.There were solid moments, in particular the on-again, off-again fugue on the text “He shall purify the sons of Levi,” which sounds so Brahmsian in character. Other passages that require more heft received none of it, however; the “unto us a Child is born” section, for example, cries out for staccato enunciation but was intoned instead with a pale slurry. Also, this part needs a strong bottom line to convey its power, but the Westminster men disappointed.

As for the soloists, there was an inverse ratio between quality of voice and ascendancy on the musical staff. John Relyea is a very impressive bass-baritone and deserves pride of place because of his fine career here in New York, both on the stage of the Metropolitan Opera and in oratorio; his voice was almost too big for the huge room. The other singers were all making their Philharmonic debuts. Mark Tucker possesses a sweet Irish tenor, fitting for a piece premiered in Dublin in 1742. Sara Mingardo made a nice recovery from low volume problems early on, and showcased a rich contralto later in the piece. Soprano Christine Brandes simply had a bad night: She was oddly straightforward during her ornamentation but wayward and sharp, with unwarranted melisma, in her textual lines. Rejoicing was the furthest emotion from my heart when she delivered the good news.

In a way, the entire historical-authenticity, period-instrument movement began with “Messiah,” when Sir George Grove (of dictionary fame) questioned the Modernist excesses of his British compatriots at the end of the 19th century. This current Phil version is decidedly Modern but expresses nostalgia for a simpler time of order and certitude. The size of the band and the simplistic nature of the music are closer to the strengths of an ensemble that doesn’t seem to be able to handle Romanticism without sinking into sentimentality and an intonational morass. Next month is the start of the Mozart year, and the Philharmonic actually has a chance to shine if Maestro Maazel and his band remember the axiom that less is more.

The Philharmonic will perform “Messiah” again December 16 & 17 at the Riverside Church (490 Riverside Drive, between 120th and 122nd Streets, 212-875-5656).