Very small.
And I still don't think he's got actual chance now. It'll be closer with Moore, but this is Alabama we are talking about. Especially in an off-year election.
It's similar to Musgrove's Senate bid in MS in 2008. It was feasible because he was a credible candidate and because of Obama producing a high African American turnout, but he still lost. Alabama's more white and more generically Republican than MS.
An off year election actually improves his chances not hurts them. The meme that Democrats always do badly in midterms is extremely inaccurate.
