Yorkshire have threatened a lifetime ban for anyone found to have made threats against Azeem Rafiq or his family and legal team.
The former Yorkshire spinner, 29, has filed a legal claim over allegations he suffered racist abuse when at the club.
The club issued a statement after ESPN Cricinfo showed them messages sent to Rafiq’s legal firm, Chadwick Lawrence.
Yorkshire said they were “appalled to learn of the threats” and “condemn them in the strongest possible terms”.
“I have received social media abuse since I spoke out about my experiences at Yorkshire,” Rafiq told ESPN Cricinfo.
“That’s been awful, but much more worrying have been threats to my family and the implicitly threatening vile messages that my team has received. It’s terrifying.”
The messages, and some social media posts, have been reported to both South Yorkshire and West Yorkshire Police.
“We understand that this is now a police matter and when the perpetrators are found we can confirm they will receive a lifetime ban from any premises owned or operated by Yorkshire County Cricket club or any of its affiliates,” added the Yorkshire statement.