Darren Lehmann, the Australia coach, is ready to put the injury-prone 33 year old into cotton wool after Australia conceded this summer's series with a 74-run defeat at Chester-le-Street on Monday.
Harris is Australia's leading wicket-taker this summer, with 20 at an average of 19.25, but his body has never before allowed him to play four Tests in a row.
After Harris' performances in the past three Tests, Lehmann knows the right-armer could be central to avoiding a 4-0 humiliation at the Kia Oval, but hinted caution over his fitness might prevail.
"We'd love him to [play at the Oval]. He's exceptional," he said. "He's had three in a row. It would be good if he gets four in a row.
"But if there's any doubt of not getting through, he won't play. To be perfectly honest the way the scenario is now we'll be extra careful with him.
"We've got to make sure he's right for the next Test series as well. He's so valuable to us as we've seen in the previous few games."
Harris reported he was feeling fit and well during the fourth Test in Durham, when his career-best figures of seven for 113 in the second innings gave his side hope of victory.
An early end in Chester-le-Street and an eight-day turnaround between Tests should aid Harris' recovery, while a desire not to become the first Australian side to lose 4-0 in England may force the tourists' hand.
"The extra day off probably helps him a week before the next game," Lehmann said.
"I just reckon he's outstanding in what he gives to the team and the way he bowls and he just gets good players out.
"The wickets he's got have been high-end all series. He's blown England away a couple of times so that's good."
Australia will also assess the fitness of Shane Watson after the all-rounder suffered a groin problem while bowling on Sunday.
Watson was subsequently able to bat, albeit making just two in the fourth-day collapse, but Lehmann ruled out the possibility of him playing only as a batsman.
"I hope he's bowling. That's what he's picked in the side to do; bat and bowl," he said.
"We'd like to have five bowlers. Our selection panel will have to sit down.
"He'd be a chance because he played very well, but he's got a value eight and his value eight is when he's bowling so we'll just have to sit down and see how he goes."
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