The 34-year-old won 48 caps for Brazil Join the Miguel Delaney: Inside Football newsletter and get behind-the-scenes access and unrivalled insight Join the Miguel Delaney: Inside Football newsletter Join the Miguel Delaney: Inside Football newsletter Email * SIGN UP I would like to be emailed about offers, events and updates from The Independent. Read our Privacy notice Former Chelsea midfielder Oscar has ​retired at the age of 34 due to ongoing cardiac problems, club Sao Paulo have confirmed.