It happened in the area of Meadow Farm Drive and Moston Road, in Shrewsbury, at about 10:30 BST on Sunday.
The car, described as silver and thought to be a Peugeot 407 or similar, with an 04 or 54 plate, was driven off down Darville.
Det Insp Mark Jones, of West Mercia Police, said there were grave concerns for the safety of the attacked man.
The attacker was a man described as white, of a stocky build and more than 6ft (1.8m) tall with an eastern European accent.
A man was attacked and thrown into the boot of a car in what police are treating as a suspected kidnapping.