Everton winger Aaron Lennon is not suffering from a long-standing mental health issue and is expected to make a full recovery in the short term, BBC Sport understands.
The 30-year-old was detained under the Mental Health Act by police over concerns for his welfare.
He was taken to hospital "for assessment" after police were called to Salford on Sunday.
It is understood his condition is a recent occurrence.
Lennon is now "receiving care and treatment for a stress-related illness", his club has said.
The England international, who joined Everton from Tottenham in 2015, has not played for the first team since February.