Liverpool's principal owner has acknowledged that the English Premier League club may have to leave Anfield for a new stadium.
John Henry's Fenway Sports Group has been considering stadium options since buying the club in October.
Responding to a fan urging him to keep Liverpool at its home of 119 years, Henry said on Twitter that a move may be inevitable.
Henry wrote: ''Anfield would certainly be our first choice. But realities may dictate otherwise. So many obstacles.''
Situated in a working-class neighborhood, Anfield is hemmed in by terraced residential housing, making any expansion extremely difficult and costly. The alternative is to build a new ground in nearby Stanley Park, which separates Anfield from Everton's Goodison Park stadium.
Anfield has a maximum capacity of 45,000 meaning that Manchester United and Arsenal raise far more revenue from tickets and other match-day revenue from their bigger stadiums. That in turn gives them greater financial muscle to attract top players on high salaries.
At 76,000, United's Old Trafford is the largest stadium in the Premier League. Arsenal moved to its 60,000-seat Emirates Stadium in 2006.
United and Arsenal have won 16 English championships between them since Liverpool's last title in 1990.