India batsman Yuvraj Singh is struggling with a hamstring injury ahead of the home Test series against England starting on March 1.
The 24-year-old left hander pulled up while scoring his match-winning 107 not out in the fifth and final one-dayer against Pakistan in Karachi on Sunday.
The victory gave India a 4-1 one-day series triumph, after the hosts had won the Test series.
"He has a strained hamstring. We will know only in the 24 hours how serious it is," team physio John Gloster said on Monday. "We will be assessing him tomorrow."
The middle-order batsman was declared the player of the one-day series after his three unbeaten knocks set up India's victory.
England are scheduled to play three Tests and seven one-dayers.
