The Chelsea man netted from close range in a 1-0 victory for the Stars and Stripes, who leapfrogged Iran into second place and sealed a spot in the last 16 in the process.
However, Pulisic collided with Iran goalkeeper Alireza Beiranvand while scoring for his country, and he remained sprawled on the floor as teammates gathered around him.
The 24-year-old was eventually taken off at half time to be replaced by Brenden Aaronson, and he was taken to hospital for examinations on the same evening, during which he posted a positive update from his bed, writing on Snapchat: "So f****** proud of my guys I'll be ready for Saturday don't worry."
The USA announced that Pulisic was dealing with a "pelvic contusion" after his scans, which led to speculation that the attacker had sustained a problem in a sensitive area.
Pulisic laid such rumours to rest in Thursday's press conference, though, telling reporters: "I didn't get hit in the balls. I'm all right. It was very painful. That [pelvic] bone is there for a reason to protect you; I hit it well. It was sore, but it's getting better," as quoted by The Guardian.
"I was a bit confused because the teammates around me were worried, I think they were just trying to keep their distance and make sure I was okay. But it didn't really feel like a celebration, so I was worried about offsides.
"I'm going to go meet now with the team medical staff and make a decision on [training] today, just kind of see how I'm feeling, taking it day by day. Right now I'm doing everything in my power to be able to be out there on the field on Saturday."
Despite his lack of starts at Chelsea, Pulisic has enjoyed a productive World Cup with the USA so far, coming up with one goal and one assist in his side's three Group G games.
The former Borussia Dortmund man has supposedly attracted interest from the likes of Arsenal, Manchester United and Newcastle United, with his contract at Stamford Bridge due to expire in 2024.
While Pulisic's importance to the US national team cannot be overstated, the attacker has insisted that he has total belief in the current crop of players to get the job done without him.
"Honestly, this team helps me so much to take the pressure off of me. A couple of years ago, there were times maybe I felt like I needed to do more," Pulisic added.
"But with these guys, I don't feel that way at all, to be honest. I know they have my back. I know when I went down, and I see Brenden [Aaronson] running onto the pitch, I'm not worried at all because I know these guys.
"I mean, you see the talent. You see the work that they put in. Just the unity of this group is what makes it special and takes any pressure that there might be off of me. They know that I got their back. They [have] got mine."
The USA will take on Group A winners Netherlands in Saturday's last-16 clash, where Gregg Berhalter must also check on the fitness of Joshua Sargent (ankle) and Weston McKennie (quadriceps).