The 18-year-old wing was included in his first Six Nations squad by new Wales coach Wayne Pivac last week but limped off at the Stade Ernest-Wallon after damaging his ankle.
Ackermann insists it is too early to know the full seriousness of the injury.
“He rolled his ankle,” said Ackermann.
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“We need to make a decision whether we need to scan it and whether we do that or he leaves for Wales on Monday and they do it.
“He felt he couldn’t run on it. He can be proud of what he’s achieved so far and mustn’t let it get him down. Whatever the outcome he can build on what he’s achieved already and opportunities will still come.
“Let’s hope it’s not too bad and he can still contribute.”
Defeat put an end to Gloucester’s Champions Cup campaign as they were outmuscled by a Toulouse side who will host Ulster in the quarter-finals.
“I am really proud of the effort right to the end,” said Ackermann.
“The scrum was under pressure, and then we made more errors in the second half. They don’t give up, this group.
“We will learn as it’s a big stage for them. When we have a full-strength squad we will be better.
“What you need is heart and passion. Toulouse pounced on every mistake we made.
“I do believe we have the ability to play against any team. Last season we were bottom of the pool while this season we had something to play for on the final weekend. I am very proud of that.”
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