Manchester United are considering expanding Old Trafford by a further 7,500 seats to increase the capacity to 75,000.
A statement from the club said other facilities at the Premiership’s biggest stadium might also be upgraded.
“A feasibility study is underway to evaluate the technical, financial and planning issues on completing the north-east and north-west quadrants.
“Any decision to proceed will be taken by the board in due course and announced thereafter.”
Every Premiership match at Old Trafford has been a sell-out since the last redevelopment was completed four years ago, prompting the club to consider a further expansion.
At present prices, the extra seats could generate in excess of £4m over the course of a season.