India has suffered defeats in all three matches they played in Group B so far and are already out of the reckoning for a place in the semi-finals of the men`s hockey competition.
"We`ve got some players out there just wanting to be Olympians, but international hockey demands heart for a fight," Nobbs said as India brace for their next game against Asian opponents South Korea on Sunday.
"The national team needs players who show the character to take up a challenge and are willing to commit their heart and body for the country`s prestige," said the Australian, who was seen singing India`s national anthem before the match against Germany yesterday.
Nobbs has strictly asked the players to make a decision whether they were willing to make that commitment to the nation and the team. "The players need to make a decision whether they are satisfied just to be Olympians and return home, or are they willing to be tough and make that commitment for the team`s cause," he said.
"If you are happy to go home having just turned up at the Olympic Games, the team cannot expect much from you," said Nobbs, who was a teammate of present Australia coach Ric Charlesworth in the 1980s.
"I come from a sporting culture where players are willing to line up their coffins on the side of the pitch. That`s their pride in representing the country."
The coach said until and unless the players take up challenges, Indian hockey will continue to suffer. "Only the good players take up challenges. If these Indian players take up the challenge, they can improve," he said.
"But that needs absolute commitment forgetting about injuries and the stuff."
Nobbs said the Indian players were not showing the attitude of winners. "Every champion and every team goes through defining moments against the odds. There are no excuses when you are on the pitch," he said.
"We need players who have attitudes of winners. Otherwise they are a waste of time where the team is concerned," he asserted.
"I am not going to pander to egos. That`s not what I am with the team for. I want absolute success for the boys. They have worked hard and given their blood and sweat to be here.
What I find surprising is the way they go soft when engaged in hard encounters," Nobbs added.
Nobbs acknowledged that Indian players were not physically tough enough. "We`re not tough, but it is a matter of self confidence. We have talent but need to be mentally tough, and that comes from performing under pressure," he said.
Looking to salvage some pride from the ongoing Olympic campaign, India will need to produce an improved show in tomorrow`s match against South Korea, who started with a 2-0 victory over New Zealand, but have lost two matches thereafter.