Trap preparing Sammon for Stockholm SOS
Of course, shackling Zlatan Ibrahimovic is the main issue that all visitors to Stockholm face, and his tendency to drop deep and play between the lines could influence the Irish thinking in terms of central midfield.
Glenn Whelan and James McCarthy are poised to start, but Paul Green is in the frame as a possible substitute if Ireland are in trouble, especially given how his arrival made a difference in last month's friendly win over Poland.
Wes Hoolahan, who also made a notable impact on the Polish match, will have to wait in reserve.
In the midst of lengthy tactical discourse, Trapattoni made it clear that there may be a time in Friday's game when a direct route to goal is needed and in that event Sammon will be sent the SOS.
"There is a moment in the game, particularly if you are tired, when you can decide to do this," he said.
Keane and Darren O'Dea will arrive in today after their MLS exploits, along with those players who were in action for their clubs yesterday.
Thirteen players were involved in the light Sunday session, including Stephen Kelly, who came face-to-face with Trapattoni for the first time since their war of words post-Poland.
"I never have a problem with players," said the manager, "The problem is the agents."
The reality, however, is that he might have to call his representatives in if he fails to devise a coherent plan for Stockholm.
A seismic week lies ahead.