Police say the 34-year-old victim was sleeping on a bench at the 14th Street station when he got into a dispute with another man around 4:15 a.m.
The dispute escalated, and authorities say the suspect stabbed him in the calf.
The victim was taken to Bellevue Hospital with a non-life threatening injury.
The dog also sustained a slash to his hind leg.
The suspect, armed with a knife, fled onto the street.
He was described as a black man wearing black pants and a brown jacket and a black hat. He was accompanied by a woman
No arrests were immediately made.
Subway service bypassed the station as police investigated.
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