You might call it unusual for a club captain to make such a statement so close to a crucial European tie, but then Lahm has never been the conventional type.
On the pitch, he is a right-back who reluctantly played on the left for the first five years of his career, and then was required to switch to midfield.
Off the pitch, he had the temerity to challenge the iconic football men who run Bayern Munich for their lack of ambition. Then he wrote a book in which he snubbed half a dozen of Germany’s leading coaches.
And all that was before going on to lift the Champions League trophy at Wembley and leading his country to World Cup triumph in Rio de Janeiro.
No surprise then that his retirement and its timing are both controversial. Carlo Ancelotti and Lahm’s previous manager Pep Guardiola feel that he could go on playing at the top level for several years.
Guardiola describes Lahm as the most intelligent player he has ever coached. “He is so natural with his football: an exceptional person, an exceptional player. He can play in 10 positions.”
“I spoke to Philipp and tried to convince him,” said Ancelotti. “But he said he wants to give 100% and not just 90.”
Players inevitably slow down in their 30s, but at the age of 33, Lahm has decided to stop playing rather earlier than some other top defenders.
His record over the past 14 years bears comparison with the best of all time, the most obvious being with Paolo Maldini, who was equally adaptable.
But Maldini played for 25 years in Serie A and was still Carlo Ancelotti’s captain at the age of 37 when he won the Champions League for the fifth time. Lahm has reached three finals, but only won it once. All the same, you can argue Lahm’s contribution to German football has been as important as Maldini’s was in Italy.
It is easy to forget that Germany — and Bayern — were at a low ebb when Lahm came on the scene. A low ebb by their standards anyway.
Germany were knocked out in the group stage of the European Championships in 2004, when they could only manage a 0-0 draw with Latvia. Two years later they hosted the World Cup, and reached the semi-final before going out to Italy. Two years after that they reached the final of Euro 2008, but then lost to Spain — as they did in the World Cup semi-final two years later.
Lahm gradually became the leading player in that revival, taking over from Michael Ballack as captain in 2010, but he was a constant critic of Germany’s performance, and particularly of coaches such as Rudi Voller and Jurgen Klinsmann. And even more critical of his club for falling behind in the European pecking order.
The fallout with Bayern peaked in 2009, when Lahm organised a newspaper interview through his agent Roman Grill, and thus broke club rules.
“Top teams in the Champions League have first-class players in seven, eight positions — we don’t,” Lahm said.
“Other clubs have a system, a philosophy, and buy the players accordingly. We don’t. It’s not enough to buy good players, one has to develop a team.”
The Bayern hierarchy — Karl-Heinz Rummenigge, Franz Beckenbauer, and Uli Hoeness — hated it, but Lahm was right. And he stuck to his guns. His autobiography in 2011, again written with his agent, criticised top coaches such as Otmar Hitzfeld and Louis van Gaal, as well as his usual targets.
Hitzfeld, to his credit, shows no resentment, and believes Lahm should just take time out before returning to a position on the Bayern board, most likely as sporting director.
But before that comes the little matter of this season’s European campaign.
Lahm timed his retirement from international football to perfection, five days after winning the World Cup. It would be a big anti-climax for Bayern to be knocked out of the Champions League at this stage.