Linderbaum vs BB Grady at Center?

I have Grady with 0ap SP and TD for 1ap. I've thought about buying Linderbaum and having Grady as his backup and subbing him in on 3rd and 4th downs and just using 0ap TD on him and saving 1ap all while still getting the benefit of TD on 3rd/4th downs and SP for 0ap on Linderbaum on 1st and 2nd downs. The good thing about Linderbaum is he gets every team chem as Grady doesn't fit my TT but that's not really a bid deal. I could just go with Linderbaum and his 0ap SP and do without Threat detector or see if another player gets it for 1ap I suppose.