Coventry City's defeat to Oxford United on Saturday looks more costly after Doncaster Rovers beat Bristol Rovers on Wednesday night.
Had the Sky Blues won against Oxford, they would have gone into the final play-off place.
However, their defeat and Doncaster beating Bristol Rovers 4-1 means that Mark Robins' side are now four points behind Doncaster who have a better goal difference to the tune of fourteen goals.
James Coppinger scored twice in the opening twelve minutes with Wilks adding a third goal in the 31st minute.
Sadler made it four straight after the restart with Bristol Rovers getting on the scoreboard with a 66th minute penalty scored by former Coventry City striker Jonson Clarke-Harris who scored his eighth goal in eight games.