A statement issued by Essex on Monday said: "Ravinder Bopara has had an ultrasound scan today (Monday) on his left thigh following a niggle picked up chasing a ball during Sunday's play (in the County Championship match against Middlesex at Lord's).
"This shows he has a strain to his left rectus femoris muscle. Ravinder was able to continue playing (on Sunday) aided by thigh strapping and standing at slip to limit aggravating this further.
"Clinically Ravi is doing well and expected to be fully fit in two to three weeks."
That would rule Bopara out of the entire one-day series against West Indies which begins with back-to-back Twenty20 matches at The Oval on June 28 and 29.
Bopara, 22, was one of England's few successes during their lacklustre World Cup campaign in the Caribbean, scoring 52 in only his fifth one-day international to take England to the brink of a win against Sri Lanka only to be dismissed off the last ball.
And with all-rounder Andrew Flintoff already injured with a recurrence of an ankle problem, a fit Bopara would have probably been included in the one-day squad due to be announced by the England selectors on Friday.