Now aged 24 and having not made a senior appearance for Reading, Williams is likely to leave the Madejski Stadium in the summer with his parent club back in the Premier League and set to be taken over by a Russian tycoon shortly.
On loan to Northampton since February, the former non-league striker has made a good impression at Sixfields and netted his third goal for the club when coming on as a substitute against Crawley on Tuesday night.
Williams was back in action straight away on Wednesday as he played and scored in a closed doors friendly against Luton Town.