According to police, the 25-year-old allegedly roughed up his wife at their home in Phoenix on July 21st and again on July 22nd.
Shortly after the incidents, cops say, Dwyer's wife left the state with their child.
Cops list 2 victims -- a 27-year-old female (his wife) and their 18-month-old child.
A report was made with cops on September 11, 2014 ... and cops have been investigating ever since.
After investigators found probable cause, they arrested Dwyer on Sept. 17th for domestic violence in Tempe.
Cops say they interviewed Dwyer and he acknowledged the incidents -- but he DENIED any physical assaults.
Dwyer is being booked into the Maricopa County Jail on 1 count of aggravated assault causing a fracture, 1 count of aggravated assault involving a minor, 2 counts of criminal damage, 1 count of preventing the use of a phone in an emergency, and assault.
The Arizona Cardinals tell TMZ Sports Dwyer has been deactivated from the roster.