Derek McInnes revealed Tomas Magnusson has gone to the hospital with a suspected fractured cheekbone sustained in Heart of Midlothian's 1-0 loss at Kilmarnock.
It was a frustrating night for the league leaders who have had their lead at the top cut to two points with Celtic having defeated Motherwell earlier in the day.
Michael Schjonning-Larsen scored the only goal of the game, ghosting in at the back post between Michael Steinwender and Alexandros Kyziridis to net in the first half.
McInnes, who named the same XI as started the 1-0 win over Aberdeen, was forced into an early change when Magnusson clashed heads with Aaron Tshibola. He was replaced by Oisin McEntee.
The Hearts head coach gave an update on his squad and is hopeful of getting three key players back for the Dundee game, but they will find out the extent of Magnusson's injury in the coming days.
"Next Saturday, we'll dust ourselves down. We'll get Lawrence back training on Tuesday. Cammy back training on Monday
"Hopefully, Benny can get back training. He felt his knee a wee bit again on Friday, which ruled him out of the squad.
"Big Magnusson, I think, is away to hospital with a fractured cheekbone, which isn't ideal.
"Harry was feeling his calf a wee bit there, so we'll see how well we are."
He added: "Listen, the boys normally respond well and I've no doubts we will next weekend. It's important that everybody reminds themselves we've got eight games to go.
"There's an unbelievable opportunity for us to go and try and do something."
McInnes is looking forward to the return of Devlin and Shankland, but wants the team to be more demanding of one another.
"Cammy was the best midfielder in the league when he went out of the team. Lawrence is the best striker in the league. If we can get that back, then of course it's going to help us," he said.
"For me, we just need to be a bit more demanding of each other. I've seen a lot of the early part of the game where we let things happen and we've got to be more demanding of each other to stop crosses, to put more pressure on, to take a step forward.
"Whether one or two were having a wee off night in that early part of the game, we can't afford to be quiet. We can't be that team. We've got to be the team we've been all season and that's bark out instructions and putting that demand on ourselves and having Cammy and your captain back, that certainly helps for that type of thing as well."
