Hall, 34, has been on trial at Sixfields and played the first 45 minutes of Saturday's friendly win at Long Buckby.
Sampson said: "We've offered Marcus a deal. He's been with us for a few days and he's done pretty well. His experience speaks for itself.
"He's played his whole career at Championship level or above, so he's got plenty of quality about him.
"He's a very fit lad, he's come in and been fantastic in all the running. The deal's on the table for him and the ball is in his court.
"He was prepared to come to Long Buckby on Saturday and he wants to play at Kettering on Tuesday night."