Aston Villa boss Steve Bruce said the injuries to Albert Adomah and Jack Grealish cost them as their run of seven straight wins ended at Fulham.
Adomah (hamstring) and Grealish (calf) missed the match, which was settled by second-half goals from Ryan Sessegnon and Floyd Ayite.
Bruce admitted there was no timescale for either to return and said they were badly missed at Craven Cottage.
Bruce said: “It’s been a cruel blow losing Albert and Grealish because they’ve given us the forward threat. They’ve been the catalyst for what we’ve achieved recently.
“We didn’t have that real penetration. When I opened us up, to get a couple of strikers on, Fulham have enjoyed that.
“Albert’s going to be a while. It’s a hamstring, so we can’t rush that. Jack was nowhere near on Friday. We’ll see how he is tomorrow.”
With Adomah and Grealish out injured, Bruce drafted in Birkir Bjarnason and Axel Tuanzebe to replace them.
Tuanzebe, the 20-year-old on loan from Manchester United, played at right-back and dealt well with Sessegnon in the first half.
“It was a terrific battle,” Bruce said. “Axel tired badly, he needs games, but you can see his talent.
“He was excellent today in his full debut for us. He’s going to be a good player, the kid.
“Where do I see his best position? Maybe centre-back – he can go into midfield as well, he’s got such pace and power and handles the ball well.
“You can play anywhere when you’re a good player.”