The Villans suffered a setback as a Jordan Rhodes second half doubled overshadowed a James Chester first half opener in the 2-1 defeat at Carrow Road.
Adomah was substituted in the 50th minute, while Abraham came off four minutes later, few seconds before Norwich registed their equalizer.
"We had two go off injured and then conceded a goal. It knocked us back a bit," Smith told AV TV.
"Unfortunately the injuries have hampered us a little bit and they score straight from the set-piece when Abraham comes off – that's usually where he heads it away.
"Albert got a knock to the knee and had to come off.
"It was a blow, that one, because I thought he was giving their full-back some real trouble.
"We've lost them, but all in all we've got to do better at defending the crosses."
The result has left Villa 16th on the league table, while Norwich occupy the fourth spot.
It is unclear if the injured duo will recover in time for Friday's trip to Queens Park Rangers.
Adomah, Villa's top scorer last season, has made 12 league appearances involving seven starts so far this term. He is yet to score this campaign.