Guāng kào tā yí ge rén, zhège xiàngmù kěndìng wánrbuzhuàn.
Relying on him alone, this project definitely won't fly.
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Northern colloquial, especially Beijing. The 儿 (-r) suffix and 玩 'to play with / handle' give it a casual, slightly self-deprecating tone — admitting something is beyond your skill or control.
usage
Positive form 玩儿得转 'can pull it off / can handle it' is equally common. Often used about machines, social situations, or running a business.
