Owen was taken away on a stretcher after twisting his knee, overshadowing a 2-2 draw that booked England into a second round match on Sunday against Ecuador in Stuttgart.
Asked if Owen would be out for the rest of the tournament, England coach Sven-Goran Eriksson said: "Maybe. I hope not, but it doesn't look good at all. Exactly what it is and how long it will take (to recover) I don't know.
"He's going to have a scan tomorrow and after that we'll see. ..let's hope for him and for us.
"I spoke to him at halftime and he was not happy. Not happy at all."
England defender Jamie Carragher said: "Michael's out of the tournament and we're just going to have to get on with it and do as well as we can with what we've got."
Midfielder Steven Gerrard added: "He's really down. We need to support him. It's not looking good."
Owen was not the only England injury suffered on Tuesday, as central defender Rio Ferdinand made way for Sol Campbell in the 56th minute.
"Rio had a small problem with his groin," Eriksson said.
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Owen fell awkwardly and twisted his right knee as he went down, forcing Eriksson to send on Peter Crouch as a fourth minute substitute.
He was hoping to avoid using Crouch as the lanky striker already has one yellow card and another would rule him out against Ecuador. He came through without a booking.
TRUE FORM
Owen had been looking to show his true form against the Swedes, having been given less than an hour in England's two previous group wins over Paraguay and Trinidad & Tobago after a lengthy absence with a broken foot.
A serious injury for the 26-year-old, who has scored 36 goals in 79 England appearances, would be a blow to their tournament prospects.
Along with Wayne Rooney, who against the Swedes was starting his first game since breaking his foot on April 29, Owen is England's only proven goalscorer at the top level.
Eriksson had gambled by taking only four strikers to Germany, with the other being 17-year-old Theo Walcott.
The teenager has only made one substitutes' appearance for England, in last month's friendly win over Hungary, and has never played for Arsenal since joining them in January.
"As other options we have Walcott, who we haven't seen on the pitch yet and many players who can take that role -- Joe Cole and Steven Gerrard -- who both scored fantastic goals today," said Eriksson. "I'm not that worried about it."
(Additional reporting by Alastair Himmer)