The 24-year-old has been out of action with a broken arm since Edinburgh's European win over Lyon in October.
And the Scottish side's medical team have now ruled out Gilchrist's chances of returning to action before Scotland's training camp for the Rugby World Cup.
"It's a big blow. It's a blow to Edinburgh and to Grant himself," Solomons said ahead of Edinburgh's PRO12 clash at Cardiff Blues on Sunday.
"He's a terrific player and plays a huge role at Edinburgh in terms of his leadership, running the lineouts. He's been a massive, massive loss to us.
"He's virtually not played for us this season, as has Cornell (du Preez), so we've had two absolutely major players playing very little rugby this year.
"These things happen in rugby and I know Grant will be well looked after. We've got very strong medical staff here."
And while Solomons was disappointed that Gilchrist would be missing for so long he was keen to reassure fans that he expects the lock to come back stronger than ever.
"Gilco knows he's getting ready for next year," he added.
"I've got total confidence in our medical staff; they're outstanding. Everybody seems confident and when they're confident, I'm confident.
"I have no doubt that Gilco will return and be raring to go come next season, and I'm sure he'll play an important part in Scotland's World Cup campaign.
"He's going to have a wee rest once he's cleared by the medical staff.
"I'd like to give him that break now because then he wants to tuck into his training and get back up to speed because he's had plenty of breaks."
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