The four stars all made their first appearance for the British & Irish Lions in Friday’s 28-24 defeat to Argentina at the Aviva Stadium, where Saints stunned Leinster just last month.
Mitchell, Smith and Freeman started, with Pollock handed game time from the bench.
And though Argentina eventually prevailed, it was a platform for the Saints players to build from as they prepare for the tour of Australia.
The Lions will now regroup as they fly Down Under ahead of their tour opener against Western Force in Perth on June 28.
Lions head coach Andy Farrell said: "We made it a tough game.
"The first and appropriate thing to say is congratulations to Argentina, they thoroughly deserved to win. They capitalised very well on quite a few errors from us, so congratulations and I'm sure that's a big moment in Argentina's history."
Bundee Aki and Tadhg Beirne scored for the Lions, who were also awarded a penalty try early in the second half, but it was not enough to beat the world's fifth-ranked team.
"You can try and throw it all around and say we had plenty of opportunities and we should have done better, but the story of the game is we compounded too many errors and weren't able to put the pace on the game that we wanted to because of that," Farrell said.
The Lions had a week-long training camp in Portugal before facing Argentina, but when asked if the squad has had enough time together, Farrell said he ‘wouldn't give that excuse’.
"We need to be better than that,” he said. “It is what it is.
"The Lions players are good players coming together. We ask a lot of them and maybe we put too much pressure on the side because it certainly looked like we were a bit disconnected at times.
"We'll review what we said we were going to own and we need to make sure we get something positive from that because it's all about how we move forward."
