The shooting occurred at 10:30 p.m. on Paragon Circle, off Foothill Road, while the 59-year-old resident was getting out of his car in his garage. The robber confronted the victim with a shotgun and demanded the man's car keys, police said.
The victim tried to hide behind a cabinet and threw some items at the robber in an attempt to scare or distract him. Instead the robber shot the man in the forearm and ran away.
Officers arrived at the victim's house within minutes but were not able to find the suspect, police said.
The victim was taken to a local hospital and is listed in stable condition early Friday.
Sgt. Mike Tryphonas said the victim will remain in the hospital for "some time" because of his injury. He was shot at a distance of less than 10 feet, Tryphonas said.
The suspect is described as Caucasian, about 25 years old, 5 feet, 8 inches tall and weighing about 150 pounds. He was wearing a dark jacket and a black or gray hat.
Anyone who has information about the crime is asked to call police at 925-931-5100.
Roman Gokhman can be reached at (925) 847-2164 or at firstname.lastname@example.org.