England bowler James Anderson hopes the injury which saw him limp off during Lancashire's match against Durham is "not too serious".
Anderson pulled up during his run-up on the third morning of the Specsavers County Championship clash at Sedbergh and sat out the rest of the day with a calf problem.
England's all-time leading wicket-taker batted with a runner on the final day but did not return to the field to bowl as Lancashire were held to a draw.
The opening Test of the Ashes series against Australia gets under way at Edgbaston on August 1.
Reflecting on the match, Anderson wrote on Instagram: "Frustrating not to get the win. Also annoying to pick up a niggle but hopefully not too serious."
While England's one-day international squad have been in World Cup action, Anderson has spent a prolonged spell with Lancashire in preparation for the Ashes.
Anderson, who was competing in his sixth game in this season's competition, has taken 30 wickets this season. The 36-year-old has a record 575 wickets in 148 Tests for England.
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