Eaves, who was a summer transfer target for boss Steve Evans, will stay at New York for 93 days and goes straight into the squad for Saturday's clash at Walsall.
"I like alot about him," Evans said of the 23-year-old. "His goal record in the Football League is one in two which is highly impressive.
"He is big and strong and he is quick. We tried to bring him in in the summer, but Dougie Freedman was having none of it.
"In the last three or four days we have been in fight with big League One clubs to get his signature. He wanted to come here and his manager wanted him to come here.
"He is very well regarded at Bolton, they bought him for a decent six-figure fee. If it was to become permanent the chairman would have to write out a serious cheque."