Fast bowler Mohammad Amir, who had initially pulled out of England tour, will join the Pakistan squad following the birth of his second daughter last week, the Pakistan Cricket Board (PCB) said on Monday.
The white-ball specialist and masseur Mohammad Imran underwent Covid-19 tests on Monday and they must register two negative results before they can join the squad in England, the board said.
"If their first tests return negative, they will be moved to a bio-secure environment in Lahore where their second tests will be conducted on Wednesday, with the expected departures over the weekend," the PCB said.
All-rounder Khushdil Shah will miss the first test against England with a fractured thumb, the board said on Sunday.
Khushdil has been ruled out for up to three weeks after injuring his left thumb while batting during Saturday's training session in Derby.
Team mate Abid Ali also survived a scare after being struck on the helmet while fielding at forward short-leg during an intra-squad match on Sunday.
"Abid is absolutely fine and will be available to resume training on Wednesday following Tuesday's rest day," team doctor Sohail Saleem said.
"He underwent a precautionary CT scan which has also returned normal."
The three-test series begins in Manchester on Aug. 5, with the last two matches scheduled in Southampton.
Beginning on Aug. 28, Pakistan will also play three Twenty20 Internationals against England with Manchester hosting all the matches.