Dale Reed Bacon, 41, allegedly attacked the older man in the 1900 block of Fifth Avenue around 1:30 p.m. Wednesday, according to San Diego police.
Medics took the manager, whose name was not released, to a hospital for treatment of severe head injuries, SDPD Sgt. Alan Hayward said.
Bacon was arrested later in the afternoon and booked into county jail.
The case was being investigated as an elder-abuse crime, according to Hayward.
The suspect was tentatively scheduled to be arraigned in downtown San Diego on Friday afternoon, a jail clerk said.
The head of the federal agency that grants citizenship and immigration benefits said Friday that he had a message for anyone who considers his new mission statement anti-immigrant: "A thousand times no."
San Diegans are starting to see a lot more bikes and scooters out and about in neighborhoods as mobile-based rental services take off with locals and tourists alike.
People arrested by deportation officers increasingly have no criminal backgrounds, according to figures released Friday, reflecting the Trump administration's commitment to cast a wider net.
Hundreds gathered Friday in Carmel Valley to raise awareness about the number one cause of death of women in America - cardiovascular disease.
Unsubstantiated threats against four San Diego-area public schools led to heightened police patrols at the campuses Friday, continuing a disturbing trend in the aftermath of last week's gun massacre at a Florida high school.
The military says a sailor was hit by a helicopter rotor blade at Camp Pendleton Marine Corps base, north of San Diego.