Root admitted after his team's loss at Old Trafford, which resulted in Australia taking a 2-1 series lead to retain the urn, that Smith had been the difference between the teams.
The England and Wales Cricket Board also confirmed Ben Stokes would not bowl in the match, which gets under way on Thursday, due to a shoulder injury, and will play as a specialist batsman.
In his column for The Sun, Anderson said he is trying to regain maximum fitness ahead of England's upcoming assignments, which include tours of New Zealand and South Africa, followed by a home series against West Indies.
Australia bounced back to win the fourth match of the series at Old Trafford after Ben Stokes inspired England to a dramatic one-wicket win in the third Test at Headingley.
With England's top-order struggling, there has been criticism of the selectors' decision to persevere with the same batting personnel throughout the series but Bayliss argued the teams picked could have been 3-0 up after the first three Tests.
Root's captaincy, and his form, has come under the spotlight but he sounded an upbeat tone as he looked forward to trying to level the series. "We came here to win the Ashes, not just to retain them".
"We've got to make sure that we square the series up and there's Test Championship points to play for as well which down the line could make a huge difference".
'We've not lost anything yet. That's the full focus of this group, so we've got to make sure that we win this game'.
Smith is banned from leadership roles until March because of his involvement in a Cape Town ball-tampering scandal a year ago but he is tipped by some former players and leading cricket writers to regain the captaincy from wicketkeeper Paine after his batting heroics in England.
"I know what direction I want to take this team forward". Of course, I've not performed as I would have liked but that's part and parcel of Test cricket, ' he added. I think over the years we've had a pretty good formula in Australia and clearly our bigger, taller faster bowlers work well in Australia so again that's where we see a really exciting six months for James Pattinson coming up and Mitchell Starc, those guys who haven't played as much during this series. "It was a tough call on Travis Head who has had a great start to his Test career".