There was good news for head coach Matt O'Connor as all of the players at his disposal took part in the session.
Ireland internationals Luke Fitzgerald and Richardt Strauss both trained and are expected to be available for selection.
Commenting on the pair's fitness, Leinster forwards coach Jono Gibbes said: "Probably niggly is the status that Straussy and Luke are in. They are not fully comfortable so you don't want to push them.
"Luke's (groin injury) is a niggly injury that could turn into a major one. We're probably being a little bit more conservative with those guys.
"They did the bulk of the training last week (for the Dragons game). Thursday morning, when we did the walk-through, there was still a little bit of pain for both of them so it was decided to take them both out of the match.
"That caused a little bit of a disruption because they had done most of the training with the team thinking they're going to play but is a frustrating part of the rehab.
"They are so close but we would probably air on the side of caution with both of them."
Meanwhile, another player, Isaac Boss, who had been a cause for some concern, was cleared to join up with the rest of the Ireland squad in Carton House.
Boss hit the ground hard in a dump tackle by Dragons replacement prop Francisco Chaparro who was sent-off in the dying minutes of Leinster's 31-19 victory.
"Bossy's initial prognosis was positive but I think they're going to take the time and have a look around, give him a day or two off," added Gibbes.
"It certainly didn't look good but Bossy was back on his feet, smiling away after the game."
The Leinster team to face Cardiff will be announced on Wednesday afternoon.