Detective Inspector John Lamb from Wishaw CID said he did not believe it was a random attack.
"It is not clear how the man came about his injuries other than what he told his friend on the phone, and I am seeking the assistance of the public to find out what happened," he said.
"Were you near to Wishaw railway station on Sunday night around 6pm and saw anyone acting suspiciously? Did you see or hear a car leave the area at speed? Did you notice anything out of the ordinary around the railway station on Sunday evening?
"The area around the station would normally be fairly quiet around 6pm on Sunday but someone may well have seen or heard something which can help officers to find out what exactly happened to this man and how he came about his injuries.
"Anyone who has any information should contact Wishaw Police Office on 01698 202655. Alternatively you can call Crimestoppers on 0800 555111 if you wish to remain anonymous."