(CNN) -- England called up Steve Harmison to their Ashes squad as they face an anxious wait on the fitness of all-rounder Andrew Flintoff for the second Test at Lord's on Thursday.
Flintoff showed glimpses of his best form with bat and ball in Cardiff.
Flintoff, who is a key member of the England team with his fast bowling and middle order batting, picked up a knee injury while fielding during the opening Test at Sophia Gardens in Cardiff.
It is a worrying development for England as Flintoff was ruled out of their opening series of the summer against the West Indies because of a knee problem picked up while playing in the Indian Premier League.
2005 Ashes hero Harmison has been pressing for a Test recall after showing fine form for his county Durham and also troubling the Australians while playing for England's second string.
In addition to the starting X1 for Cardiff, England's 14-man squad also includes back-up batsman Ian Bell and Harmison's county colleague Graham Onions.
"We have added Steve Harmison to our squad for the next Test match as Andrew Flintoff injured his right knee at Cardiff and will undergo a precautionary scan later today, said national selector Geoff Miller.
"Andrew is experiencing soreness and swelling in the knee which he twisted while in the field and he will be reassessed by the medical staff over the next 48 hours leading up to the Test match on Thursday," he told Sky Sports News.
Australia have not lost a Test at Lord's since 1934 and will start favorites after their domination of the opener which saw England's last pair of James Anderson and Monty Panesar hold out for a draw in a dramatic finish.