Liverpool and Manchester United have both sent scouts to watch Portuguese international Rolando, according to reports.
The Porto defender has impressed with a string of impressive performances in his homeland this season, leading to speculation that Barclays Premier League teams are keen to bring the player to England.
Kenny Dalglish is reportedly considering his defensive options at Anfield, and the Liverpool chief has hinted that he could make additions in the summer with the backing of new owners NESV.
Manchester United, meanwhile, are thought to be keen on adding defensive reinforcements at Old Trafford. With injuries taking their toll on the side this season, the Scotsman believes more strength-in-depth is needed.
"On Wednesday, there were observers to follow him from many clubs including Inter Milan, Juventus, Manchester United and Liverpool," said agent Peppino Tirri, according to Calciomercato.
"The player's rating is very high. €15 million (£12.7m)? Even a little more."
Valuation is not thought to be a problem for either side, as both clubs have money to spend. Liverpool proved that in January, spending over £55 million on two strikers to replace Fernando Torres.
The arrival of Luis Suarez and Andy Carroll has led to an upturn in fortunes for the Reds in recent weeks, and Dalglish will hope to continue this in Liverpool's challenge for a European place.
Manchester United will have the lure of Champions League football for Rolando, who moved to Porto in 2008 after four years with Belenenses.
The 25-year-old centre back has eight international caps for Portugal, and would provide Manchester United with domestic, european and international experience should they move for the player.
Competition is fierce with interest from abroad also, and Liverpool or Manchester United will have to move fast if they wish to secure the signature.