Sergei Filin, a 42-year-old former ballet star, was approached late Thursday night by an unknown man who threw the acid at his face as he got out of his car outside his home in central Moscow, city police spokesman Arkady Bashirov said. Theater officials said the man was masked.
The theater's general director, Anatoly Iksanov, said he believed the attack was linked to Filin's work.
"He is a man of principle and never compromised," Iksanov said on Channel One state television. "If he believed that this or that dancer was not ready or was unable to perform this or that part, he would turn them down."
Filin knew that someone was trying to threaten him or undermine his position at the theater, Iksanov said. He said Filin's car tires had been slashed earlier this week and he was targeted in early January by hackers who posted his professional correspondence online.
"He said 'I have a feeling that I am on the front lines,'" Iksanov quoted Filin as telling him Thursday before the attack.
Filin, who danced for the Bolshoi from 1989 until 2007, was appointed artistic director of the Bolshoi's ballet company in March 2011. Before returning to the Bolshoi, he served as artistic director at the Stanislavsky and Nemirovich-Danchenko Theater, Moscow's second ballet company.
Bolshoi spokeswoman Katerina Novikova, who visited Filin in the hospital Thursday night, told The Associated Press that his condition is stable but he could lose his sight.
"We never imagined that a war for roles — not for real estate or for oil — could reach this level of crime," Novikova said on Channel One.
Several stars at the Bolshoi including Nikolai Tsiskaridze, one of its most celebrated dancers, have complained about what they call Filin's unfair treatment of dancers at the Bolshoi.
Alexei Ratmansky, who served as Bolshoi artistic director from 2004 until 2008, described an atmosphere of intrigue at the theater.
"What happened with Sergei Filin was not accidental," Ratmansky, now artist in residence at the American Ballet Theater, posted on his Facebook page. "The Bolshoi has many ills. It's a disgusting cesspool, of those developing friendships with the artists, the speculators and scalpers, the half-crazy fans, ready to bite the throats of the rivals of their favorites, the cynical hackers, the lies in the press and the scandalous interviews of staff.
"This is all one snowball caused by the lack of any ethics at the theater."