O'Connor, who was speaking after his side had slipped to a seventh defeat in eight league outings as Wycombe Wanderers secured three crucial points on Easter Monday, insisted that he will not pick players who haven't got a will to fight, before calling upon his squad to step up to the challenge.
Along with this weekend's clash with the Posh, Walsall face a final day trip to Montgomery Waters Meadow, where they will take on Shrewsbury Town with the Saddlers needing to secure maximum points from both games if they are to retain even the slimmest of hopes of securing survival.
The Saddlers have been in decline since the opening few weeks of the season and will have to return to the level of performance which was produced during that period, which saw them defy the bookies odds and sit amongst the form sides as the season got underway.
Speaking via the Express & Star, Martin said; "I’ll be there when we train, I’ll be there against Peterborough and I’ll be there against Shrewsbury. I think that’s the nature of me and I have to have a squad of players who feel the same.
"The door will be open this week for anyone who doesn’t fancy playing against Peterborough and anyone who doesn’t fancy playing against Shrewsbury. I’ll be honest, for me everyone should be wanting to play.
"If they don’t want to play they shouldn’t be at the football club. We are four points adrift with two games to go, we have got to put in performances. We’ve been saying that for how long.
"It’s come down to this situation and we have to be looking at ourselves. You can’t be blaming anyone else. We have to look at ourselves and try and put in a performance."
The Saddlers's last three outings – against Accrington Stanley, Southend United and Wycombe Wanderers – represented a huge opportunity to dent some of their relegation rivals' hopes of survival whilst also climbing away from danger, and O'Connor admits that his side simply failed to capitalise.
Skip continued; "They are missed opportunities. We have said that after every game. This feeling has been coming for months. Two or three months. It’s the group of players we have got.
"They have been honest and they have said a few comments to me - which I accept. But what I can do is get a team out there on Saturday who hopefully will play without fear and try and get a result."