PORT ADELAIDE forward Zak Butters has had successful surgery to release pressure on the nerve injury around his left knee that he suffered in the Round 4 win over Richmond.

The 20-year-old started running earlier this month with his ankle recovering from a syndesmosis rupture suffered in the same incident, but the associated nerve damage around his knee has delayed his return.

After seeking a number of specialist opinions on further options to manage the nerve injury, the advice was that an operation to release the pressure on the nerve was the best option to ensure a full recovery.

A timeframe for Butters’ return to the field will be determined in coming weeks.