Frostad added that the condition could affect Trout’s long-term prospects.
“We really have to look at this as something… he has to get through this not only for the rest of this season, but maybe for the rest of his career,” he said, according to MLB.com.
Following those comments, Trout himself reached out to reporters following the Angels’ 4-0 victory over the Kansas City Royals on Wednesday night to clarify the news and downplay its severity.
“I appreciate all prayer requests, but my career is not over yet,” said the 10-time All-Star, according to the Orange County roster.
Trout left a game against Houston on July 12 with back spasms and was listed for injury a week later with chest inflammation before the underlying condition was diagnosed.
He withdrew from the All-Star Game and received a cortisone shot last week but will be out of training for at least another week.
“The last two days have been huge steps. I’m delighted with how things are going. I’m happy with that,” Trout added.
Although he hopes to return this season, Trout admitted he will have to “keep up with the regime” to deal with the illness.
It marks a setback for the second highest paid player in the game during his comeback season, in which he hit .270 with 24 home runs and 51 RBIs in 79 games after a calf injury that saw him miss most of last year.
Trout has another appointment with the doctor on Sunday.