The 24-year-old So'oialo was brought on at inside centre against Saracens at the Sportsground for his first Connacht appearance.
Up front, Galway native Andrew Browne replaces the injured John Muldoon at blindside flanker. Most notably on the bench, David McSharry makes a return to the Connacht squad this weekend.
The 24-year-old McSharry, who earned his first Ireland Wolfhounds cap last season, got game-time with UCD and Connacht Eagles in recent weeks.
The talented centre's last outing for Connacht came against Zebre in last January's Heineken Cup pool game.
Commenting on the team selection, Lam said: "Losing John Muldoon to injury, along with Eoin McKeon and Willie Faloon, was a huge blow to our back row. But Andrew Browne comes in as a straight replacement at 6 and has plenty of experience in that position.
The Connacht boss added: "Against Zebre we're under no illusions of the challenge we face. This is a game that they are desperate to win in their own back yard and they have openly targeted this one.
"But, after a good week's training, it's a challenge we look forward to facing head on."
CONNACHT (v Zebre): James So'oialo; Danie Poolman, Robbie Henshaw, Craig Ronaldson, Matt Healy; Dan Parks, Kieran Marmion; Brett Wilkinson, Sean Henry, Rodney Ah You, Michael Swift (capt), Craig Clarke, Andrew Browne, Jake Heenan, George Naoupu.
Replacements: Jason Harris-Wright, JP Cooney, Ronan Loughney, Aly Muldowney, Mata Fifita, Paul O'Donohoe, David McSharry, Gavin Duffy.