(CNN) -

Four days after Neymar was kneed in the back, Brazil face the real possibility of being booted out of their own World Cup when they take on Germany in the semifinal at Belo Horizonte on Tuesday.

The hosts will have to manage without their star striker after he sustained a fractured vertebra in the 2-1 quarterfinal win over Colombia in Fortaleza.

It's not just in attack that Brazil have problems -- captain and key defender Thiago Silva is suspended after picking up his second yellow card of the tournament in the same match.

Neymar's injury is a huge blow to the hosts who, under coach Luiz Felipe Scolari are looking to reach the final for the first time in 12 years in their hunt for a sixth world crown.

Wild celebrations following Friday's win became more muted when news filtered through that Neymar -- scorer of four goals in five matches in Brazil's campaign --would play no further part in the tournament.

"It's like we have lost today," a female Brazilian fan in Rio de Janeiro told CNN after hearing of the seriousness of Neymar's injury.

"It's terrible, terrible. I'm so sad. But let's go on."

Sympathy also came flooding in from fans and arch rivals -- old and new.

"It concerns not only the Brazilian people but all of us who love football," Argentine legend Diego Maradona told the Venezuela-based Telesur TV network.

"It was his World Cup, in his country. He had great hopes."

The Albicelestes current playmaker Lionel Messi also responded, posting a message for his Barcelona teammate on his Facebook page.

"Neymar, I hope you recover very soon, friend!" Messi wrote while German midfielder Mesut Ozil tweeted: "Neymar, I am unhappy. get well soon."

Such is the fevered speculation surrounding Neymar there were even suggestions the Barcelona star could play if he had painkilling injections or underwent emergency surgery.

That speculation was quickly put to rest by the Brazilian Football Association Monday who said such treatment would not happen as it would would endanger Neymar's future career.

Dreams of a miraculous return were perhaps fueled by Brazil's obvious reliance on their stricken star.

The 22-year-old talisman has scored 35 goals in 54 international appearances -- three more than the combined totals of the squad's other forwards -- Fred, Hulk and Jo -- have managed in total in matches for the Selecao.

"Brazil are too dependent on Neymar," former Brazil midfielder Juninho told CNN following the group stages.

"If Neymar plays well, Brazil plays well. If he doesn't, nobody can do his job. It's a worry. It's like Portugal with Ronaldo."

A member of Brazil's last World Cup winning squad in 2002, Juninho also queried whether the current side have the experience to sustain their challenge.

"When you wear a Brazilian shirt you are under pressure even now when you play in your country. I think the players need to know how to deal with that.

"All of the players have a lot of experience in European competition but not in the national team and in the World Cup -- for a lot of them this is their first World Cup."

Brazil's winning captain in 1970, Carlos Alberto, struck a more positive note ahead of the Germany clash when he recalled the impact Garrincha made when he deputized for the injured Pele 52 years ago.

"In the 1962 World Cup, we lost Pele," Alberto told Sportv.

"Maybe someone will wake up and become the Garrincha of 1962."

Another Brazilian great -- former midfielder Zico -- hopes a Neymar-less Brazil can prosper if Scolari deploys more "combative" midfielders.

"In my mind, fast players like Willian and Bernard need to be considered ..." Zico wrote in UK newspaper The Observer on Sunday.

"Above all, the Brazilian players have the chance to draw energy from Neymar's sacrifice ... they need to leave their souls on the pitch as a tribute for this kid whose dreams have been shattered because of one horrific tackle," Zico concluded.

Three-time champions Germany come into Tuesday's crunch match buoyed by a typically robust 1-0 win over France in the quarterfinals.

Joachim Low's side are seeking a first World Cup win in 24 years after narrow misses in the last three tournaments.

In 2002, Germany were runners up to Brazil -- the only World Cup meeting between the teams -- before losing at the semifinal stage to eventual winners Italy and Spain in 2006 and 2010 respectively.

A hugely experienced squad -- five players have 100 caps or more -- must quietly fancy their chances against an under-strength Brazil.

Not that anyone is saying that publicly.

"We're all sad that Neymar can't play, it's always better when the opponent has all their best players on the pitch," Germany midfielder Bastian Schweinsteiger told FIFA.com.

"It'll bring the (Brazil) team together and they'll want to win the title for him."

Schweinsteiger also pointed to the pedigree of Brazil's coaching team -- noting both Scolari and technical director Carlos Alberto Parreira have previously managed Brazil to victory (in 2002 and 1994 respectively) -- and that home advantage shouldn't be underestimated.

"Their coaches have a lot of experience of this kind of situation. It's an honor and a challenge to play against the hosts, but it have would be better to play Brazil in the final," Schweinsteiger said.

"It doesn't matter how much experience you have, to play the hosts in this football-crazy country, I mean that in a positive sense, is something special."

The task of officiating this clash of two World Cup titans has been handed to Marco Rodriguez.

Players from both sides will be hoping that he is alert to all incidents -- the 40-year-old Mexican failed to spot Luis Suarez's bite on defender Giorio Chiellini when Uruguay played Italy in the group stages last month.

Referring to Carlos Velasco Carballo's leniency in officiating Brazil's win over Colombia -- only two Brazilians were booked by the Spanish referee despite the Selecao's 31 fouls -- Schweinsteiger urged Rodriguez to be watchful.