Gasol, who left Barclays Center on crutches, admitted he is "worried" about the injury. The four-time All-Star is scheduled to undergo an MRI on the foot Wednesday after the Lakers travel to Boston.
"I tweaked my fascia in the first half, so I was dealing with quite a bit of soreness in the second half," said Gasol, who left the game with 3:50 remaining. "So I couldn't do certain things.
"I was dealing with it, but that play when I tried to jump off of it and try go block the shot (by Brooklyn's Brook Lopez), just as I took off, I felt a pop in the bottom of my foot on my fascia and I couldn't get up. I'm worried about it."
Last week, Gasol said he was playing through a pain level of eight out of 10 in his right foot.
"I've been dealing with it for a couple months now," Gasol said. "But I never felt anything like I did tonight. Right now it's a certain level of strain. We just don't know how bad it is."
Gasol initially tried to play through the injury. But after one trip up and down the floor, he asked coach Mike D'Antoni for a sub and went to the locker room with Lakers trainer Gary Vitti.
"It felt kind of OK a little bit putting my weight on it without walking or running, but once I started running, I was limping and it was really sore," Gasol said. "Even if I tried, I couldn't go."
Gasol was unsure how long he could be sidelined if the injury turns out to be too severe to play through.
"I've had some injuries before," he said. "They're never pleasant, they're never fun. But right now, I'm a little bit uncertain how long this thing is going to take."
Gasol finished with 15 points, four rebounds and two blocks in the Lakers' 92-83 win.
Gasol got the start Tuesday night but had been coming off the bench in recent games, something he chafed at.
"(Gasol) didn't like coming off (the bench)," D'Antoni told "The Michael Kay Show" on ESPN NY 98.7 FM on Wednesday. "That's just the way it is. I was hoping that he would settle into it, but never really did. Now it's kind of a moot point because he's hurt and he's going to be out for a while. So, we'll figure it out when he comes back."
Gasol's return remains unknown, but the injury has led to concern for others on the Lakers' roster.
"I'm very, very concerned about it," Kobe Bryant said. "Obviously, we don't know the extent or the severity of the injury yet. But I'm very, very concerned to say the least."
Gasol has missed 13 games this season due to tendinitis in both knees and a concussion.
"I've been playing with the fasciitis, which is painful and uncomfortable and limiting; this is something different," Gasol said. "We'll find out (Wednesday). Right now it's really sore, but hopefully it will get better. ... With the MRI, I'll know exactly what I have and what's next."
When asked after Tuesday's game whether he would play against the Celtics, Howard said: "I'm not talking about that right now."
Bryant said Howard, who missed just six games through his first seven seasons in Orlando, simply has to learn how to play through injuries.
"I think it's an experience thing," Bryant said. "Like for me, when I was growing up in high school and middle school, unfortunately but fortunately, I dealt with injuries. Not injuries that are debilitating, but injuries that you have to play through and you have to manage the pain. So when you go through those things, you learn your body and you know what you can push through and know what you can't push through.
"But Dwight's never been hurt. ... So when you have an injury that hurts you, but you can play through it, that's something that you have to balance out and manage. He's never had to do that."