Rotherham United fear the worst as they prepare for Kyle Vassell injury verdict

The forward pulled up only 12 minutes into last Saturday's 1-1 League One home draw with Tranmere Rovers and had to be replaced by new boy Chiedozie Ogbene.

The 26-year-old is being assessed by the club's medical staff and Millers manager Paul Warne is braced for bad news.

"Hamstring injuries are never good for power athletes, that's for sure," the boss said after his side had been hit by a Rovers equaliser deep into stoppage time at AESSEAL New York Stadium.

"I never pulled my hamstring as a player because I was never quick enough.

"Vass is a power athlete, so that could be four, six, maybe eight weeks out depending on the severity of the injury. We won't know that until Monday."

Vassell's absence will be a big blow to the Millers, who head to the Keepmoat Stadium on Saturday for a derby against Doncaster Rovers, as he has been a key man in their 4-3-3 formation.

"Vass has been excellent in pre-season and in all of the games since the season started," Warne said. "He adds a bit of flair.

"I always threaten the lads that I will make a substitution if I have to, but I didn't want to be making one after 12 minutes."

Ogbene, signed last week from Brentford, put himself in contention for his first start at the weekend by lighting up New York with his second-half display on his debut.