Ninjaman put into the jar and keep safe at a shrine. In Timeranger episode, Timeranger member had activate time-travelling event to protect this shrine from being destroyed. So, it was a great canonical link between all series and clear up some trivial events in Super Sentai canon here.
Ninjaman is needed by Gokaiger team as the last super sentai power before they can achieved the Greatest Tresure. But Ninjaman still reluctant to surrender his power, in the far sight, Tsuruhime (White Kakuranger) was monitoring the events and seems approved to what Gokaiger and Ninjaman rendesvouz.
Two pictures from Gokaiger Episode 45, a tribute to Ninjaman.
Ninjaman, entertainment by Luka Millfy (Mao Ichimichi)
Ninjaman in late 2011