12 Dec, 14:42
Prop Cian Healy is expected to miss the start of the 2014 RBS 6 Nations after undergoing surgery on his injured ankle on Wednesday.
Best and Henry combined well during the Ireland 'A' side's Churchill Cup final victory over England Saxons in the summer.
There is also an exciting young centre partnership of Darren Cave and Fergus McFadden which could set Belfast alight on Friday night.
Up front, Mike Ross and debutant Brett Wilkinson will anchor the front row, with a vacancy left at hooker pending the Ireland senior team announcement tomorrow.
Devin Toner and Donnacha Ryan will link up in a Leinster-Munster lock combination. Ryan is one of eight players with Test match experienced in the Irish starting line-up.
Shane Horgan, who will captain the Ireland 'A' side on the night, is one of a number of players hoping to press their claims for senior squad recognition in the weeks and months ahead.
"I think anyone playing for Ireland 'A', their ultimate goal is to either achieve representative honours for Ireland or to get back in the senior side as is the case with me," Horgan told IrishRugby.ie.
"It's very exciting to be playing with this 'A' team and I'm delighted to be captaining it because there's so many good players - guys are being rewarded for the form they have shown right from the beginning of the season through all the provinces and the guys over in England as well.
"That's the good thing about the 'A' team, no matter who you're playing or where you're playing, there's always huge motivation externally to lift yourself to the next level and it's nice to be involved with players with that sort of ambition."
Horgan has not played against Tonga before but he did feature against the Pacific Islanders side in the last ever international to be played at the old Lansdowne Road in November 2006, scoring a try to boot.
"They bring a massive physicality and aggression to every game they play," said the big Leinster winger, when asked about what he expects from the Tongans.
"We've seen their performances in World Cups and whenever we've travelled down to the South Pacific you know you're in for a tough game.
"When they've played against us as a national side or as part of the Pacific Islanders team a few years ago, they were super physical and they brought a real flair to the game.
"I think it will be an exciting match. Hopefully the conditions will allow both sides to play rugby, but It will certainly be a physical game."
As a proud Ulsterman, Ireland 'A' team manager Joey Miles is particularly pleased that Ravenhill will host the first 'A' international of the season.
"I'm delighted it's being played in Belfast. I just hope the Ulster rugby public come out and support it," he said.
"It's one of the things that the IRFU think long and hard about, moving the internationals around the provincial bases.
"It's really up to the rugby public now to come out and support the IRFU on that decision. But, yes, I'm personally delighted to be in Belfast."
Tickets for Friday's clash Tonga are currently available online from Ulster Rugby - click here. Do not miss out on your chance to see some of Ireland's bright young stars in action against the hard-hitting visitors.
IRELAND 'A' TEAM & REPLACEMENTS (v Tonga, 'A' International, Ravenhill, Friday, November 13, kick-off 7pm):
15. Gavin Duffy (Galwegians/Connacht)
14. Shane Horgan (Boyne/Leinster) (capt)
13. Darren Cave (Belfast Harlequins/Ulster)
12. Fergus McFadden (Old Belvedere/Leinster)
11. Andrew Trimble (Ballymena/Ulster)
10. Ian Humphreys (Ballymena/Ulster)
9. Peter Stringer (Shannon/Munster)
1. Brett Wilkinson (Galwegians/Connacht)
2. AN Other
3. Mike Ross (Clontarf/Leinster)
4. Donnacha Ryan (Shannon/Munster)
5. Devin Toner (Lansdowne/Leinster)
6. Neil Best (Northampton Saints)
7. Sean O'Brien (Clontarf/Leinster)
8. Chris Henry (Ballymena/Ulster)
16. Denis Fogarty (Cork Constitution/Munster)
17. Bryan Young (Ballymena/Ulster)
18. Dan Tuohy (Ballymena/Ulster)
19. Kevin McLaughlin (St. Mary's College/Leinster)
20. Isaac Boss (Ballymena/Ulster)
21. Ian Keatley (Galwegians/Connacht)
22. Johne Murphy (Leicester Tigers)