Scotland international Rhodes, 25, was stretchered off in the first half of Rovers’ friendly at Accrington on Saturday and was later pictured leaving the Store First Stadium on crutches and in a protective boot.
Rhodes, who has scored 74 goals in three seasons at Ewood Park, was therefore absent when Gary Bowyer’s men jetted off to the continent.
However, should the news on Rhodes’ injury be positive, Rovers stressed that he will fly out to Portugal to join his team-mates later in the week.
Speaking about Rhodes’ injury in the immediate aftermath of the victory over Stanley, Bowyer said: “He’s just got a knock on his ankle but it is too early to assess it at this moment.
“We’ll see how he is on Sunday and we’ll go from there. Hopefully it was just precautionary that he came off. He’s in very good hands with the medical team that we have at Brockhall.”
The travelling party that Bowyer has taken to Portugal includes four trialists – ex-Sheffield Wednesday midfielder Giles Coke, South Africa international Dean Furman, former Crewe youngster Liam Nolan and Frenchman Sacha Petshi.
There are no plans to play a fixture during their week in Portugal and Blackburn will next be in action against Rochdale in eight days’ time.