This summary is logical. It preserves the organizational strategy. Bringing back Gagner allows the prospects to maintain their incubation.

As for filling the defensive hole, not that Joel Persson is out a minimum of 7 days is tricker. Caleb Jones is versatile. He can play both the left and the right side. William Lagesson was the last player cut at training camp. Both players can play.

The injury recall and the player selected is a tell for the organization.
The replacement may be considered higher up the development chart. That may not be the case inside the organization.

The state strategy is to let prospects develop and keep them in the AHL rather than calling them up and sending them back. Ironically, the Oilers don't have room on defence for all the players they currently have.

Three prospects, Evan Bouchard, Caleb Jones, and William Lagesson have all demonstrated over the last two seasons they are very close to playing in the NHL.

Whoever gets the injury re-call is auditioning not just in Edmonton, but for 31 other NHL teams.
https://thesportsdaily.com/2019/10/17/time-for-oilers-to-recall-sam-gagner/