Faisal Halim, 26, who suffered burn injuries on his neck, hands, chest and shoulder, is expected to be back by August
The Hammers have moved to replace David Moyes with the Spaniard, who was a candidate for the Bayern Munich job this summer
The 57-year-old Spaniard replaces David Moyes, who left when his contract expired at the end of the season.
Lopetegui has previously been in charge at Porto, Spain, Real Madrid and Sevilla prior to a brief stint with Wolves.