Two weeks, four weeks, six weeks ... Rotherham United wait on Clark Robertson scan verdict

The centre-half returned to the side only in January following a year during which he played just two games because of groin and foot surgeries.

A 15th-minute departure from Saturday's 1-0 Championship home loss against Reading with a hamstring issue means even more time on the sidelines for the unlucky player.

The 27-year-old is undergoing a scan and the Millers anticipate a recovery spell of up to a month but fear the Scot's absence could be longer.

"We took him off before he did any serious damage," manager Paul Warne said. "He'll be out for between two to four weeks, I’d suggest. But if it's a grade 1 pull it could be more like six."

Robertson, coming to the end of his three-year deal at AESSEAL New York Stadium, was offered a new contract in February ago but said he wanted to wait until the end of the season before making a decision.

The Millers, who had five long-term injury victims earlier in the campaign, have been hit by a fresh round of problems, with midfielder Jamie Lindsay (hamstring), centre-half Richard Wood (groin) and now Robertson all missing matches.

Winger Chiedozie Ogbene (knee) hasn't played since September and left-back Joe Mattock's troublesome ankle has kept him out for the last three months.

The Millers, in the drop zone after five straight defeats, will have to struggle though the next six games, starting with Wednesday's trip to derby rivals Sheffield Wednesday, on limited numbers.

Then, from March 20, there is a fortnight-long gap in their packed fixture schedule during which they can finally regroup.

"We just need to get to the international break and then we’ll have players back," Warne said. "Jamie, Chieo and possibly Joe should be available then."

Central defender Michael Ihiekwe misses the Owls showdown as he completes a two-match ban but there is a chance captain Wood could be fit to return.