Leo Cullen says new recruit James Lowe needs more time to embed himself in the Leinster system, although he admits he was tempted to call upon the services of the exciting winger for their Champions Cup fixture this weekend.
The province face Exeter on Sunday but the Kiwi is not listed in the squad, partly due to the Champions Cup rule which states that each team can only pick two "overseas players" in a match-day 23.
Lowe has impressed since his arrival, scoring two tries in a man-of-the-match debut against Benetton Treviso in the Pro14 last weekend.
Cullen, however, said that giving Lowe more time to adjust to the new environment was part of the decision to hold him in reserve.
"We're very conscious that James has come off two seasons really. He was with the Chiefs and he went to Tasman. Even though it's a shorter tournament, a lot of games (are) condensed into a shorter period of time.
"We're lucky we have a lot of competition in that three at the moment.
"Traditionally, back row and back three are probably where we have had the highest injury rate and unavailability. We're just being cautious there and it gives us the opportunity to get a week's training in there to embed him in the system.
"We do things a bit different to what he'd be used to so that's why we held off."
The team named to start the tie sees Robbie Henshaw and Garry Ringrose partner up in Leinster's midfield as Henshaw makes his return from a hamstring injury. Ringrose also previously suffered from a shoulder injury.
Sunday's game will mark their first game linking up together at club level in this campaign.
Cullen says that although they are lacking in game time experience together, the management devised ways to ensure they were involved in the preparations.
"Garry being out injured, you're always waiting to see what those guys are like when they come back. With the shoulder injury, he had the advantage that he was able to do a lot of training without the contact part so he was pretty well up to speed during that block prior to him coming back. He did pretty well in the game away against Treviso
"Over the course of the last season, he's built up a pretty good relationship with Robbie."
Leinster were dealt a personnel blow earlier this week, following the news that Jordi Murphy will join Ulster next summer on a two-year contract.
This brings the Dubliner's seven-year association with the side to an end, and he said in a statement earlier this week that it was 'an incredibly hard decision to leave Leinster.'
Cullen offered his best wishes to Murphy as he prepares to move up north.
"We respect his decision and wish him all the best. He hopefully will play a huge role for us between now and the end of the season as well. Hopefully we'll send him away with some happy memories."
Listen to exclusive Champions Cup radio commentary of Exeter v Leinster on RTÉ Radio One’s Sunday Sport programme (kick-off 5.30pm).
Live updates of Munster v Leicester on Saturday (7.35pm) and Sunday’s games featuring Harlequins v Ulster (1pm) and Exeter v Leinster (5.30pm) on RTÉ.ie and the News Now app.