"He'll be evaluated later today and then a decision will be made as to whether he'll need further tests," Bradley said Sunday. "Obviously he was sore -- did a great job of taking a tough hit, and staying in it and playing really well. But we'll assess him later today and figure out then what we need to do from there."
Howard was injured when Heskey's foot slid into him in the 29th minute Saturday night. Howard was down for a while, saying he felt "in agony." When the game resumed, he grimaced several times.
Howard played the second half after having an injection of a painkiller and made six saves as the United States rallied for a 1-1 tie.
"Any time you're in a big game like that and you get injured, there's no chance anybody is taking you off that field. And Tim is no different than the rest of us," defender Steve Cherundolo said. "Having a good goalkeeper in a tournament like this is essential, so we're very happy Tim is on our team, and I'm certain he'll continue with his good performances."
Bradley couldn't say if Howard's participation in Friday's game against Slovenia was in doubt. Slovenia played Algeria on Sunday in Group C.
"At this time I think there's no answer," Bradley said. "But when you see the way Timmy handled himself after the collision last night, you'd certainly expect he'll be on the field again."
Howard, the starter for Everton in the Premier League, is backed by Wolverhampton's Marcus Hahnemann on the U.S. team. Brad Guzan, the backup to Brad Friedel on Aston Villa, is the No. 3 American goalkeeper.
Howard said after the game in Rustenburg that he felt sore, but that team doctors at first impression didn't think there was a break. The U.S. team then made the two-hour trip back to its base camp in Irene.
"In a couple hours I'll be struggling," he said before leaving Royal Bafokeng Stadium in northern South Africa. "It's going to take me a few days."
Howard was disappointed at allowing Steven Gerrard's early goal, but pleased with the way the Americans rallied on Clint Dempsey's 40th-minute goal. Dempsey's 25-yard shot bounced twice and went in off the hands of goalkeeper Robert Green, a major blunder.
Howard saved the Americans time and again in the second half, frustrating the famous high-priced stars he faces each week in the Premier League.
Howard made a point-blank stop on Heskey's 18-yard right-footed shot in the 52nd minute and parried Frank Lampard's 20-foot left-footed shot over the crossbar in the 63rd.
"I don't know what it is about us," Howard said. "We're resilient -- always after we get the punch in the face."
With each save late in the game, louder chants of "U-S-A!" erupted from Sam's Army and American Outlaws, groups who made the long and expensive trip from home to sit among the vuvuzela-blowing fans on a cool night in the Southern Hemisphere.
"I think when you play at the highest level and against the best competition, it will bring the best out of you," Howard said.
Gerrard put England ahead in the fourth minute, blowing past Ricardo Clark to beat Howard from short range.
But Dempsey tied the score when his 25-yard shot skipped past Green, yet another in a long line of shocking gaffes by England goalkeepers. It made Dempsey only the second American to score in two World Cups, joining Brian McBride.
The result was a thrill for the U.S. and a disappointment for England, which is looking for its first World Cup title since 1966.
Jozy Altidore nearly put the Americans ahead in the 65th minute with a shot that went off Green's hand and the upper corner of the goal. Howard then withstood a late barrage by the English, and was named man of the match for saving the U.S. from its defensive lapses.
While not a shocking win to match the 1-0 American upset over England at the 1950 World Cup in Brazil, the U.S. earned a huge point its quest to reach the second round for the first time since 2002.
Gerrard scored his 17th goal in 82 appearances, bursting past Clark. Heskey took Glen Johnson's throw-in and sent a through ball to Gerrard, who flicked it past Howard.
Dempsey scored on a play very similar to the goal by Croatia's Niko Kranjcar that went in off Scott Carson's arm and helped eliminate England from qualifying from the 2008 European Championship.
Dempsey took several touches, spun around Gerrard and hit a dipping left-footed shot. The ball hit the field twice, glanced off Green's right hand and went into the net for Dempsey's 19th goal in 63 national team games. Dempsey also scored against Ghana as the U.S. was eliminated in 2006.
Information from The Associated Press was used in this report.