Another 24 pub staff are now self-isolating after two teams have been identified who may have put them in contact with the confirmed case, Lancashire Live reports.
The Covid-19 test was completed on July 27 and came back positive on July 30.
The pub therefore closed early on July 31 due to the large number of staff who were unable to enter because they have to isolate themselves.
The pub has provided contact details for 24 staff members to public health officials, but no details about the client have yet been requested.
Wetherspoon spokesman Eddie Gershon said: “Wetherspoon has made the decision to temporarily close the pub.
“The local authority did not advise the company to close the pub.
“Local authorities and public health organizations have been very helpful and supportive.
“Details of testing and tracing clients have not yet been requested by authorities but are available if needed.
“Wetherspoon will reopen the pub as and when it can secure the number of staff needed to do so safely. “