The Royal Blues have won only one of their first eight league matches this term and Metzelder admits his side are now in a relegation battle.
"The situation is getting more and more precarious by the week," he said.
"We are making too many errors. Each year, there are teams who perform below their ability and then get stuck in a relegation dogfight.
"The way things stand today, we are definitely stuck in a relegation battle."
Hertha Berlin were relegated last season, just 12 months after narrowly missing out on a Champions League spot, and Metzelder knows Schalke must act fast to ensure they move out of danger before it is too late.
"I still believe there is a lot of room for improvement," the former Germany international added. "At least that is positive."
Coach Felix Magath refused to criticise his team, however. Once again, only the result did not match his expectations.
"A 2-2 is too little for us, yet we performed well enough, which is why I am happy with my players' efforts," he said.
"We have got to build on this performance in our coming games."
Jens Keller, who was making his debut on the Stuttgart bench after Christian Gross was sacked on Wednesday, was more satisfied with the result than his side's performance.
"This point will do us good," he said. "We lost a bit of energy and organisation after the interval and that allowed Schalke to create more chances, but overall I am happy."
The Swabians remain bottom of the table with just four points from the first eight matches.