New signing Shaun Harrad scored on his debut in midweek as the Cobblers romped to a 6-2 win over Crewe and is hoping to form a partnership with Leon McKenzie.
But McKay - who also scored against the Alex after coming off the bench - has managed nine goals this season and remains an important part of the squad.
Sampson said: "Leon McKenzie and Shaun Harrad linked up well on Tuesday and I was delighted for Shaun to get a goal on his debut.
"If we can keep Leon fit those two will make a decent partnership but Billy McKay is pushing them both hard.
"Billy is our top goalscorer this season and I'm sure there is plenty more to come from him. If Leon is not fit for Saturday then Billy is a ready-made replacement."
Source: PA
Source: PA