Newman suffered a ruptured thigh muscle in a Premier League Cup meeting nearly three weeks ago and made his Poole return in the 48-42 win over Birmingham on Wednesday.
However, the reserve was troubled by his injury and will sit out tonight’s trip to Wolverhampton (7.30pm) ahead of what is likely to be a week on the sidelines.
Middleditch is keen for Newman to take all the recovery time he needs if it means the 20-year-old is back to 100 per cent sooner.
The team manager told the Daily Echo: “He’s still in a great deal of pain and I don’t want him to injure himself any further and jeopardise our chance of winning the meeting against Wolverhampton.
“He needs a bit more physio just to get it sorted because he wasn’t fit when he came back against Birmingham.
“He needs to be honest with himself as well as us because he was in a great deal of pain and halfway through the meeting I thought he was going to have to pull out.
“He went through the pain barrier and did exceptionally well, so respect to him for that, but I don’t particularly want him to risk racing on his own track, I’d sooner use a guest if someone’s available.
“Riders tend to come back from injuries too early and it’s often not the best decision. Kyle had an accident in heat two and although he wasn’t hurt, it could have set him back weeks or even months.”
Pirates do not to expect to make an announcement on a replacement for axed reserve Lee Smart until tomorrow, with Charles Wright and Luke Crang guesting in the absence of the Swindon-born rider and Newman.
Meanwhile, Pirates’ charger Vaclav Milik qualified for the World Under-21 Championship in emphatic style on Saturday.
The Czech won his semi-final in Terenzano, Italy after defeating Denmark’s Nicolaj Busk Jakobsen in a run-off.
Milik will now take his place in the three-round series that begins in Lonigo, Italy on Saturday, July 19, the same night that Poole travel to Eastbourne.
Wolverhampton Wolves: (from) Tai Woffinden, Jacob Thorssell, Ricky Wells, Ty Proctor, Piotr Pawlicki, Joe Jacobs, Ashley Morris.