Liverpool midfielder Adam Lallana could miss the start of the new season after injuring a knee in training.
The 26-year-old, who moved to Anfield from Southampton earlier this month, sustained a knock to his lateral collateral ligament during a session at the Reds' Harvard University training base in Boston.
Although no timeframe has been placed on a return to fitness, such injuries can result in a spell of anywhere up to six weeks on the sidelines.
Liverpool's first Barclays Premier League match is at home to Southampton on 17 August, 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.
Lallana, a boyhood Everton fan, completed his £25m move to Anfield earlier this month, ending manager Brendan Rodgers' pursuit of a player he identified as a primary target for this summer.