Sweden coach Lars Lagerback, whose team faces Italy, Denmark and Bulgaria in the group phase of the European championship finals in Portugal, said Larsson's change of heart was positive.
"I have just now spoken with Lars Lagerback. I told him that if he...still wants me for Portugal I'll be happy to join," the regional daily Helsingborgs Dagblad newspaper quoted Larsson as saying on Friday.
He quit international soccer after the 2002 World Cup finals where he was not fully fit but made a one-off appearance in a Euro 2004 qualifier in April 2003.
"Everyone must have the right to change his mind. I've longed for the European championship all the time but I have not been sure until now. I feel in great shape physically," Larsson said.
He declined to speculate about what impact he might make, but Lagerback was confident: "Because of the kind of football Henrik has displayed this season and the kind of person he is, this is a positive injection for the national team," he told Swedish TT news agency.
Lagerback said it was too early to say whether Larsson, who has scored 36 goals for Celtic this season, would team up with Ajax striker Zlatan Ibrahimovic in Sweden's attack -- a dream formation said local media on Friday.
"Sweden's chances and team morale increased by something like, let's say 75 percent... we're bringing our heavy artillery to the European championship finals," wrote Helsingborgs Dagblad soccer commentator Stefan Lindqvist.
Larsson, 32, has played 73 internationals for Sweden, scoring 24 goals. He won the Golden Boot award as top scorer in European club football in 2000-2001 and was voted Scottish player of the year in 2001.
