70-year-old Edward Avery testified Thursday that he never touched his accuser but feared a long sentence if convicted at trial.
The same accuser says he was raped by Avery, the Rev. Charles Engelhardt and ex-teacher Bernard Shero in about 1999.
Engelhardt and Shero are on trial.
Avery's testimony could bolster the defense. But prosecutors note that Avery still faces a civil suit and harassment in prison.
A jury last year convicted Monsignor William Lynn of child endangerment for placing Avery in a parish despite an earlier sex-abuse complaint.
On the stand, Avery admitted to that earlier complaint. But asked if he raped the man accusing Engelhardt and Shero, Avery said: "I did not. So help me God."