After taking a heavy blow to his ankle late in the first half, De Bruyne was then substituted early in the second half during Belgium’s 1-0 win.
TV footage later showed the double PFA Player of the Year nursing his ankle with a protective ice pack.
However, De Bruyne – who celebrates his 30th birthday today – later flew out to Munich with the rest of the Belgium squad as they began preparations ahead of Friday’s quarter-final with Italy.
And addressing the media today, Martínez provided the latest news on both De Bruyne and Eden Hazard who was also forced off through injury against Portugal.
"It's quite positive for us. Eden and Kevin have no structural damage,” the Belgian boss confirmed.
“They will remain with the squad. We won't get them fully fit for Friday. In the next phase they will be fit to play. We take it day by day."