Young was one of half a dozen players made available for transfer at the end of the season if the price was right.
O'Neill said: "There has been an offer from a football club which Luke is mulling over and, if it doesn't materialise, then he would join us in Portugal (for the Guadiana Cup)."
The 31-year-old was a key performer during his first campaign at Villa after making a £5million switch from Middlesbrough during the summer of 2008.
But he suffered early injury problems last season, then was given compassionate leave after the death of his brother, and saw Carlos Cuellar cement his position at right-back.
Fellow defender James Collins will have a scan today to determine the extent of the calf injury suffered during last night's friendly with Walsall at the Banks's Stadium.
The Wales international was substituted after only three minutes of Villa's 2-1 success.