The forward, who enjoyed an encouraging pre-season campaign leading the line, picked up a problem during the friendly against Atletico Madrid in Oslo.
It meant he was sidelined for the visit of Graham Potter's side and, with Cristiano Ronaldo not fully match fit after getting his first pre-season minutes under his belt in the first half of the draw with Rayo Vallecano, a major switch was required on Sunday.
New signing Christian Eriksen was pushed into a 'false-nine' role for his competitive debut and only reverted back to a deeper position after Ronaldo was introduced from the bench during the second half.