The Joffrey Ballet has been plagued with injuries during the whole of its short Wolf Trap season. There have been so many changes of ballets and personnel -- last night there was even a replacement of a replacement -- it's a minor miracle the dancers have been able to keep things straight. Last night, both "La Vivandiere' and "Postcards" were scratched, being replaced by repeat performances of "Night" and "Cakewalk."

The program opened as planned with Gerald Arpino's frantic, folksy "Celebration." The ballet matches the driving pulse of its Shostakovich score and has a lot of flash, but you're never sure what's being celebrated. The dancers are supposed to be ballet peasants -- there's a lot of heel-toe work and hands are most often behind the head or on the hip -- but the dancers don't seem to know each other. As in Arpino's "Suite Saint-Saens," the choreography is so fast it seems impossible that the dancers don't crash into each other. One waits for a lyric interlude that never comes -- it's the slam-bam-thank-you-ma'am school of choreography.

In Gray Veredon's "Unfolding" (danced a few weeks ago at the Joffrey II's gala at Lisner, but a Wolf Trap premiere), the dancers get to know each other only halfway through the ballet. Like Hans Van Manen and Choo San Goh, Veredon starts with his four couples uninvolved, dancing rather sedately, until they discover romance and rejection at midpoint. Then the men seem to think the women don't like them, although they've allowed themselves to be lifted and hoisted without demur.Emotions unfold more than steps in this ballet. It's less interesting than "Celebration" -- it lacks the sense of physical danger -- but the two ballets share the same problem of anonymity. The dancers in both works performed their assignments well.

After this, Laura Dean's pungent "Night" was as refreshing as a cool breeze would have been. Here, although the dancers often perform the same steps simultaneously, they're never anonymous. Each clearly has a place in Dean's mysterious, repetitive rite. Mark Goldweber was riveting "Night." Without doing anything to call attention to himself, merely spinning twice as fast as everyone else, off in his own orbit, Goldweber's decisive, clean movements became the spine of the dance.