England fast bowler Jofra Archer is set to miss the third Test against South Africa, with Mark Wood likely to play.
The tourists were deciding between Archer, Wood and Chris Woakes to replace the injured James Anderson for the match in Port Elizabeth, which begins on Thursday.
But Archer has not completely recovered from his right elbow injury and Wood is in line for his first competitive game since the World Cup final in July.
The four-Test series is level at 1-1.
“The reason we’ve been quite cautious in terms of rushing Mark back is his history of injury,” said Root.
“But every now and then, you can’t worry about whether he’s going to get through a five-day game.
“If they’ve proven themselves to be fit, if they’ve jumped through every hoop and worked very hard to get back there, you have to give them that opportunity.”
Like Archer, Wood offers extreme pace, as well as reverse swing, but had knee surgery after the World Cup and has not played Test cricket since starring against West Indies in St Lucia 11 months ago.
“If he’s 100 per cent, bowling at 90mph-plus, the skills he has at that pace are going to cause problems and will be a great asset in Test cricket,” said Root.
Anderson, England’s all-time leading Test wicket-taker, suffered a rib injury during the second Test victory at Cape Town that has ruled him out of the rest of the series.
Archer played in the first Test, but missed the second with an elbow problem.
Woakes last played in the second Test against New Zealand in December. Along with Archer and Wood, he was struck down with the illness that hit the England squad before and during the first Test defeat at Centurion Park.
Root said that Archer’s elbow injury was “a little bit of pushback from his body” after playing a “huge amount of cricket” since making his England debut in May.
“If he’s fit and raring to go you want him in your side but you want to make sure he’s 100 per cent ready and he can deliver all his skills,” said Root.
“We’ve got to look after him as a player and his career as well as just trying to win the series.”
The victory in the second Test was England’s first in Cape Town since 1957 and was achieved with five players aged 24 or under. All of the five – Dom Sibley, Zak Crawley, Ollie Pope, Sam Curran and Dom Bess – are set to play in Port Elizabeth.
“Your best win is your next one, but that was a very enjoyable one,” said Root of the success in Cape Town.
“It was a massive moment for us, to level it up. It gives us nothing going into this game other than momentum and we have to make sure we follow that up.
“From a young team, it’s really important that we don’t live off that win for the rest of this tour. We have to try to try to exceed it.”
Wicketkeeper Jos Buttler was fined following the second Test after stump microphones caught him swearing at South Africa’s Vernon Philander.
“Jos has taken his reprimand and apologised. He knows that’s not the sort of language you want to be using on the cricket field,” said Root.
“You don’t want to take away that niggle, that competitive element that brings the best out of players on the field. Getting the balance right, using the right language, but being competitive is still a good thing. You don’t want to completely sanitise the game, but we know our responsibilities.
“In a way you’d like him to choose his words more carefully, but as a captain it shows how much it means to him.”
Fast bowler Anrich Nortje said Buttler could face some hostile bowling in the third Test after swearing at Philander.
“It definitely gets one or two guys going,” said Nortje. “It’s not really something you can say on a stump mic.
“That’s for umpires and whoever to sort out but it does get the blood flowing, and once we identify a moment, we will probably try to rev it up.” (Cricinfo)