The Wolves striker, 20, arrived at Edgar Street towards the end of August.
Winnall's first goal clinched a 1-0 win over Dagenham & Redbridge, which remains the Bulls' only league victory this season, while his second came in the 6-1 defeat at the hands of Gillingham.
He is now able to take his place in Jamie Pitman's matchday squad for Saturday's home clash against Oxford after extending his stay into a second month.
Source: Team Talk
Source: Team Talk