Felix Jones, who had an injury-disrupted start to the season, will make his second Heineken Cup start for the province at full-back, linking up with captain Doug Howlett and Simon Zebo in a talent-laden back-three.
Earls returned to the outside centre berth against Glasgow Warriors last weekend after the November internationals and he retains that jersey at the expense of Casey Laulala, who offers a very potent back option from the bench.
And with back-rowers Niall Ronan, Sean Dougall and Tommy O'Donnell all on the injury list, opportunity knocks for David O'Callaghan who has been handed the blindside berth for what will be his first Heineken Cup start.
O'Callaghan, a 22-year-old Development-contracted player from Youghal, County Cork, came on as a replacement in the final pool game last season against Northampton Saints.
Given the blight on the back rows, Coughlan's return is particularly opportune. He has confounded the medics by returning from a groin tear way ahead of schedule. He proved his fitness with a 75-minute shift against Glasgow.
Recent Ireland debutant David Kilcoyne will make his third successive European start in the front row, less than a week before his 24th birthday.
At the other end of the scale it will be out-half O'Gara's 106th appearance in the Heineken Cup. His record points tally for the tournament currently stands at 1303 points.
MUNSTER (v Saracens): Felix Jones; Doug Howlett (capt), Keith Earls, James Downey, Simon Zebo; Ronan O'Gara, Conor Murray; David Kilcoyne, Mike Sherry, BJ Botha, Donncha O'Callaghan, Donnacha Ryan, David O'Callaghan, Peter O'Mahony, James Coughlan.
Replacements: Damien Varley, Wian du Preez, Stephen Archer, Billy Holland, Paddy Butler, Duncan Williams, Ian Keatley, Casey Laulala.