The skipper put in a tremendous performance at the heart of defence in the 4-1 win over Fulham amid Wolves' injury and illness crisis.
It was the first time Lemina had played in a back four and O'Neil now sees him as a viable option in that department when needed.
The head coach said: "Things can change, but off the back of last weekend, I think he's a legitimate option for us at centre-back, especially with the quality that we have available to us in midfield.
"But Santi and Dawson have been in good form and they're both back fit."