A thigh injury threatens to prevent Liam Plunkett from replacing Steven Finn in England's limited-overs squads to face South Africa.
Finn was ruled out of the remainder of England's tour on Monday owing to a left side strain, with Plunkett named as the 26-year-old's replacement for the upcoming one-day international and Twenty20 contests.
However, Plunkett has subsequently picked up a thigh problem while on duty with England Lions.
He sat out the first of two 50-over matches against Pakistan A on Wednesday and his planned link-up with the senior squad has been delayed.
A statement on the England and Wales Cricket Board's (ECB) website read: "Liam Plunkett was ruled out of the opening match with a strained muscle in his left thigh.
"England have therefore revised their plans for Plunkett to fly to South Africa at the weekend, after playing two matches for the Lions, to join their preparations for the one-day and T20 series against the Proteas.
"Plunkett will have a further test tomorrow [Thursday] to check on his fitness for the second match of the Lions series on Friday."