Mikel Obi sustained a wrist injury during Nigeria’s 2-0 win over Iceland at the Volgograd Arena on Friday.
The Tianjin TEDA midfielder could be seen moving gingerly towards the end of the encounter, sparking fears he could sit out the match against Argentina.
But Rohr has moved to calm the doubts in the minds of fans.
“No issues with Mikel Obi, he will recover in time for the next game,” he told journalists after the game.
Nigeria need to avoid defeat against Argentina, to qualify for the knockout stages.