New Zealand coach Darren Bazeley said Chris Wood does not appear to have suffered a serious injury after the Nottingham Forest forward limped out of their Europa League win over Porto before halftime on Thursday.
New Zealand's captain and leading goalscorer is set to play a key role for the All Whites at the World Cup in North America, with their first game against Iran set for 15 June.
The 34-year-old, who only returned to action this month following a lengthy layoff due to a knee injury which required surgery, was substituted early in the first half after a heavy tackle by Porto defender Jan Bednarek, who was shown a straight red card.
Forest won the second leg of their quarterfinal 1-0 to advance 2-1 on aggregate.
"While you obviously never want to see our players go down injured, the impact was on the other knee to where he recently had surgery," Bazeley said in a statement to New Zealand media.
"He will be assessed by Forest but it doesn't sound like it is as serious as it first looked, thankfully."
New Zealand will also face Egypt and Belgium in Group G as they return to the World Cup for the first time since the 2010 edition in South Africa.