Leitch-Smith came off the bench to net the winner as Steve Davis' side beat Scunthorpe 1-0 at Gresty Road.
Defender Harry Davis sustained a toe injury during the match and is a doubt having made way for Mark Ellis with an hour played.
The Railwaymen have no other injury problems and assistant manager Neil Baker is relishing the prospect of taking on the Sky Blues at a sold out Ricoh Arena.
"It will be a difficult game but we have two legs to get through and I'm sure Coventry will be looking at it the same way," he told Crewe's official website.
"It is a sell-out there, so it will be a great atmosphere for the players to play in and we will bring a lot of away supporters as well to get behind us. It is something to look forward to."