Baker, a first-round pick who had been starting at left tackle, will not play in Sunday's game at Oakland and it's not known when he might return, coach Mike Smith said.
"We've aggressively treated it and it has not responded," Smith said Tuesday, an off day for the players. "Our medical staff suggested he goes and seeks other opinions. Like with all our players, we want to do our due diligence. Sam will be missing practice for the next couple of days getting his hip looked at."
Baker's hip appeared to be improving last week. He returned to practice and Smith thought he would play against Philadelphia.
When the problem flared up again, Baker didn't dress for the 27-14 loss to the Eagles. Todd Weiner took over at left tackle but wasn't able to finish the game because of an ailing knee.
While Smith believes Weiner will be healthy enough to play against the Raiders, the Falcons are likely to make a roster move to bolster their line depth.
"That's something we're looking at," the coach said. "We can't rule it out."
Baker, the Falcons' second pick of the first round after quarterback Matt Ryan, won the starting job in training camp but has endured an injury-plagued season. He also missed time with a concussion.
His ailing hip will be examined by two specialists.
"Sam is such a competitive guy that he wants to get back as quick as he can," Smith said. "This is a 16-game season. It's not a one-game season. We want to make sure we do what's in the best interest of the player and the team for the long term."