Hassan’s injury, picked in the Soldiers’ 1-0 win against Kakamega Homeboyz, is not as bad as initially thought.
Head coach Dunstan Nyaudo is closely monitoring the progress of Rio's recovery ahead of Sunday’s home clash against Rangers at Afraha Stadium.
"It is not as serious as initially thought. He landed badly and sprained his ankle, but I talked to the doctor and he says it is not bad.
"We will have an assessment on him in the week and see if he can play the next game," Nyaudo told the club's official website.
The Soldiers are sixth on the log with 10 points, three above Posta Rangers, who have won only one of their six fixtures.
Ulinzi Stars are yet to lose a home game at Afraha Stadium in Nakuru this season.