UPDATE, 10 am ET Monday: Citing "a person familiar with the situation," the Atlanta Journal-Constitution's Doug Roberson reports that Martinez will be sidelined "several weeks," a timetable that would put the star striker in contention to return during the Audi 2019 MLS Cup Playoffs.
Following Roberson's report, Atlanta head coach Frank de Boer updated media on Martinez's condition at Atlanta's Monday morning training session, though didn't offer a specific timetable:
UPDATE, 5 pm ET Sunday: ESPN analyst Taylor Twellman gave Atlanta fans some reason for optimism about Martinez's situation on Sunday, as he tweeted out the following:
Twellman subsequently discussed the matter at halftime of the Portland-Minnesota broadcast on ESPN, adding that "Over the last two to three hours, Atlanta United believe that this is more weeks than months, which is a positive [development] … if it’s a three- to four-week injury, their first playoff game, from today, is four weeks … Atlanta United, as of right now, believe Josef Martinez, the injury isn’t as serious. But I remind everyone [it's uncertain] until the tests are done and until they have the final diagnosis – they’re waiting for the pain to come down."
Returning in a matter of weeks should mean Martinez is ready to go when the Audi 2019 MLS Cup Playoffs kick off on October 19.
A collision, followed by an awkward landing in the second half that caused Martinez to be substituted out in the 79th minute, led to the sight of Martinez in tears on the sideline, followed by a medical crew carrying him off the Mercedes-Benz Field on a stretcher, a towel covering his face.
While it appeared to be a knee injury, Atlanta United head coach Frank de Boer said the team would likely learn more in evaluating the star striker Sunday.
"Probably tomorrow we can have a better diagnosis and then we have to make our plan," he told reporters after the win. "Hopefully it's not so bad. But I can't say if it's good or bad. I don't know."
De Boer was optimistic despite an initial diagnosis not being forthcoming, but he admitted the images on the field weren't exactly inspiring.
"We know Josef a little bit -- he's a tough guy. He will not suddenly step off the field. He will have something, that's for sure. But we have to wait. It's too early to predict. But I think it's not a good sign that he goes off ... but it's like that. We have to deal with it. Again, we have to wait."
Speaking to Spanish-language media later in his press conference, De Boer sounded a more downbeat tone.
"I'm afraid that he has something serious, but we have to wait," he said. "They're evaluating him now."
"First of all we have to wait, but I'm in soccer so long now other players would have to step up in that moment," De Boer said. "If he's out for one or two games or more then other players have to stand up. That's what they're training for – to step in. And I warn them every time, every moment – be patient, your chance will come. But then you have to be ready.
"Hopefully other people will stand up. I'm going to see which one will replace him if he's injured. Hopefully, I don't have to think about it," De Boer added.