Police say the attack happened around 8 a.m. on November 29 on Amsterdam Avenue in Hamilton Heights.
Surveillance video shows the suspect, wearing a black hoodie, pulling an orange baseball bat out of his pants and striking a 47-year-old man in the back of the head.
The victim fell to the ground. He summered a laceration to his head as well as bruising.
EMS took the victim to the hospital. He was listed in stable condition.
The attacker ran away and has not been caught. He was described as a male with a light complexion.
Anyone with information in regard to this incident is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782). The public can also submit their tips by logging onto the Crime Stoppers website at https://crimestoppers.nypdonline.org/, or on Twitter @NYPDTips.
All calls are strictly confidential.