West Ham boss David Moyes hopes to "crack the code" that will restore Kalvin Phillips to top form.
The midfielder joined the Hammers on loan from Manchester City in January in an effort to preserve his England place at Euro 2024.
However, he missed out on Gareth Southgate's latest squad, with the England boss saying he "couldn't be confident" in Phillips' current form.
He made two starts in 16 Premier League appearances in 18 months at City.
"I hope we can crack the code before our time runs out," Moyes said.
Phillips has struggled for consistency since the move.