German midfielder Marco Reus was ruled out of the tournament yesterday with an ankle injury sustained in their final warm-up game on Friday.
Germany, who face Portugal, Ghana and the United States in Group G, left for Brazil last night with 22-year-old Sampdoria defender Shkodran Mustafi drafted in to replace Reus.
The Borussia Dortmund player turned his ankle just before half time in Germany's 6-1 win over Armenia in Mainz, partially tearing a ligament.
"Both for him and for us it is extremely bitter," coach Joachim Löw said. "Marco was in top form both in training and in the friendlies. He played a central role in our planning."
Mustafi, who won his only cap in May against Poland, was one of three players omitted from the final squad of 23.
"It was not about replacing Marco Reus," Löw added. "We have a lot of quality in that position with Lukas Podolski, Andre Schürrle, Mario Götze, Thomas Müller, Mesut Özil, Julian Draxler and Toni Kroos. That is why we decided for an option in defence with Mustafi."
Republic of Ireland defender Richard Keogh has called Costa Rica's Giancarlo Gonzalez "stupid" for elbowing Kevin Doyle in a friendly, leaving the Irish striker needing five stitches.
Gonzalez was sent off for the clash during the Republic's 1-1 draw with the World Cup-bound Central Americans in Philadelphia early yesterday.
Keogh said: "It was stupid, he deserved to be sent off. You don't want to see that on a football pitch. I hope he learns from it because he has let his team-mates down and let his country down.
"It was a poor challenge. Even their players were apologising."
Ireland led through Doyle's 18th-minute header, but Costa Rica equalised through Celso Borges's 64th-minute penalty.
Cristiano Ronaldo and Raul Meireles have boosted Portugal by resuming training to ease concerns that they would miss the opening Group G game against Germany in nine days' time.