Lallana injury doubt for Liverpool
Adam Lallana plays for England against Costa Rica in a World Cup game in Belo Horizonte on June 24, 2014 - by Fabrice Coffrini
The 26-year-old midfielder, who moved to Anfield from Southampton earlier this month strained a ligament during a session at the Reds' Harvard University training base in Boston.
There was no word on how long he would be sidelined for, but such injuries can result in a spell of anywhere up to six weeks out of action.
By chance Liverpool's season-opener is at home to Southampton on August 17, with Lallana now facing a fitness race to make the Anfield clash.
He has been assessed by Liverpool's medical staff and does not require surgery.
However, the news is clearly a setback for the England international, who will undergo further assessment by the club's medical team in the United States and on his return to Liverpool.
Striker Rickie Lambert, Lallana's England team-mate, also made the move from Southampton to Liverpool while Croatia defender Dejan Lovren is widely expected to follow the same path.