Officers are investigating an alleged attack to a volunteer supporting Proposition 8, a measure that would ban same-sex marriage, Modesto police said.
Jose Nunez, 37, told police that he was jumped Sunday while distributing yard signs in front of the St. Stanislaus Parish, officials said.
Nunez was taken to a nearby hospital where he received stitches under his eye.
In response, No on Prop. 8 campaign director Patrick Guerrier released a news statement that said, "the No on Prop 8 campaign condemns violence of any sort. We are deeply concerned to hear the news of a lawn-sign incident that apparently involved the injury of one of the volunteers for the Yes on 8 campaign. This incident -- or anything like it -- should not be tolerated in any campaign."