Midfielder Coutts has missed the last three games with a hamstring injury but looks set to be passed fit.
Left-back Williams is also line for a return after an ankle injury, leaving Paul Parry (tendonitis) and Barry Nicholson (broken leg) as North End's only absentees.
Preston's play-off hopes are over but Ferguson has warned his players they are not yet safe from relegation.
And the Deepdale boss may consider changes after he accused his players of shooting themselves in the foot in last weekend's 2-2 draw at home to QPR.
North End were 2-0 up and cruising but allowed Rangers to hit back and level to secure a point.