But fullback Israel Dagg appears to be making progress with his groin injury and may play the Hurricanes on Saturday.
Five-eighth Michael Hobbs, who is recovering from a badly bruised thigh, trained yesterday and is also a possible starter.
First five-eighth Mathew Berquist is struggling with a hamstring strain, while No 8 Nasi Manu is also in major doubt for Saturday's match at Carisbrook.
Manu damaged his knee six minutes into the first game of the season in February and has not been seen since.
He strained a hamstring during his recovery and coach Glenn Moore said he was still doubtful for Saturday.
Manu is the sort of the player who needs matches under his belt to get some match fitness.
Loose forward John Hardie is recovering from a medial ligament strain in his knee and should be right to take the field.
Romans and Macdonald were released from the Highlanders camp last week in their bye week, to get some playing time, but it backfired somewhat on coach Glenn Moore.
Moore though was philosophical about the loss of the two players, saying yesterday that players could not be wrapped in cotton wool, and had to keep playing to retain match fitness.
Romans badly tore his right hamstring while playing for University A against Alhambra-Union.
He is expected to be out for between four and six weeks, and will not play for the Highlanders again this season.
Macdonald ruptured his right Achilles tendon - he did his left about three years ago - while playing for Taieri against Pirates and has already had it operated on.
He is beginning the long road to recovery, expected to take six months.
Macdonald's injury means he is unlikely to feature in Otago's provincial campaign.
His injury is another blow to the Highlanders engine room, which has been hard hit this season.
Key lock and All Black Tom Donnelly injured his ankle five rounds into the competition and was forced to have an operation, and his Super 14 season appears over.
Vice-captain prop Jamie Mackintosh suffered a turf toe injury last month and has missed the past two games.
He is hopeful of returning to the side in the final two rounds.
Dunedin hooker Sam Anderson-Heather was the hooker in the Highlanders wider training group but he broke his leg in club play on April 10 and is out for a lengthy period.
Harbour hooker Peter Mirrielees has been called into the side and will sit on the bench for the match on Saturday night.
Southland halfback Scott Cowan, the younger brother of captain Jimmy Cowan, joins the side, and will also sit on the bench.
Dagg, who has been one of the Highlanders' standouts this year, missed the game against the Force, after straining his groin in training a day before the game.
It was the first minute he had not played for the Highlanders after 21 straight games.
But he was doing some light training yesterday, and his availability for Saturday's match will be assessed later in the week.
