Luai was on Saturday morning charged by the match review committee, but its grade-one nature means he can accept a fine.
There were fears the Penrith five-eighth had got himself into trouble when he hit Drinkwater marginally after he passed the ball, leaving the Cowboy requiring a HIA.
There were also questions following the 22-0 win on whether the hit was a shoulder charge.
Luai was hoping for the best after play and was confident he would avoid any serious sanction.
"I'm not really worried. I just tried to read the play," Luai said.
"Scott Drinkwater has been really good for them.
"I didn't realise I hit him in the head. I spoke to him after the game and he's all good, so hopefully I don't get in too much trouble for it."
The committee backed that on Saturday, with Luai able to accept a $1,000 fine.
The No.6 could be one of seven Panthers picked in the Blues' squad on Sunday night, alongside fellow certainties Nathan Cleary, Isaah Yeo and Brian To'o.
Stephen Crichton is a likely pick at centre, Liam Martin an incumbent in the back row and Apisai Koroisau an option for either the bench or the role of 18th man.
Cleary did not take the last shot at goal after being hit late on a kick by Jordan McLean, which he told referee Ashley Klein was dangerous.
"He just got a cork, just hobbled around. So he should be fine," coach Ivan Cleary said.
"I had a view that kick pressure has changed again tonight. Because we never ever get kick pressure penalties.
"And he was tackled multiple times tonight late and in the air and whatever. Maybe it (the rule) has changed."
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