Duo out for table-toppers
New Irn-Bru First Division leaders Morton entertain bottom of the table Dumbarton without the injured David Graham and Steven Stirling.
Greenock boss Allan Moore believes the Sons' 4-3 win at Falkirk on Saturday has done his men a favour.
"Their win is a very timely reminder that you cannot assume anything in football," he said.
"They will take a tremendous boost from it and Ian Murray will be delighted to break his duck, so we know that we have to turn up and work hard to earn the three points.
"We have hit top spot and want to stay there but that brings pressure. Thankfully it is a pressure some of our boys have been through successfully in the past and that will help in a game like this."
Dumbarton are without the banned James Creaney and injured player/ manager Ian Murray as well as Pat Walker and Kevin Nicol.
Goalkeeper Stephen Grindlay is available after a one game ban with the Sons having a spring in their step after winning for only the second time this season at the weekend.
Murray said: "It was great to start a run of games against the top four sides in the division with a win.
"We took our chances well against Falkirk and we will need to be as ruthless again against Morton as we may not get too many openings.
"It will be a big ask to win at Cappielow but we will go there with some confidence and work hard to get a result."