Spurs boss Mauricio Pochettino admitted the full-back's fitness was uncertain after he finished the Wembley encounter on crutches and wearing a protective boot.
Trippier hobbled away from an early clash with Alex Sandro and, despite setting up Harry Kane for the opener, needed to be substituted before half-time.
"The feeling now is better than at half-time. Until we assess him and do a scan, we need to wait," Pochettino said, with the trip to Newcastle to come on August 13.
"I cannot guess [whether he will be fit for Newcastle] because we need to wait until Monday.
"We hope it's not a big problem."
Trippier's potential absence leaves a hole at right-back, following the sale of Kyle Walker to Manchester City, with Pochettino indicating England Under-20 international Kyle Walker-Peters was not ready for a first-team berth.
The Argentinian did confirm that Spurs were pursuing multiple targets having not yet added to their senior squad over the off-season.
"We are working, trying to add some players to the squad," Pochettino said.
"It's a little bit difficult for a club like us. But we follow our plan and try now before the end of the transfer window, when everything happens, to get the targets that we want and the players we want to bring here."