Ellison (30) has signed for the Ricoh club in Japan but it was hoped he would get a dispensation from the New Zealand Rugby Union to come back and play for the Highlanders next season.
The dispensation bid was declined by the NZRU board at a meeting over the weekend in Wellington.
Highlanders general manager Roger Clark said it was disappointing to not be able to get Ellison back.
Although he had not been told the reasons Ellison had not been given approval, Clark said the national union did not want to set a precedent for players to be going back and forward from Japan.
The NZRU wanted players picked from the ITM Cup.
He also said the union was talking to Woodcock about next year. The All Black prop had been linked with his old franchise, the Blues.
Woodcock had a contract to play for the Highlanders for another year but Clark said he had some personal issues with his family and was talking to the franchise. At this stage he was still with the Highlanders.
Clark said Hore's contract for next season would not be discussed until the end of the season, which had been the approach for both player and franchise over the past couple of years.
But with Liam Coltman making great strides this year, Hore's future- he turns 35 next month - appears to be in doubt. Hore captained the team to a disappointing 14th this season.
New Zealand Maori first five-eighths Willie Ripia is also on the Highlanders' radar, but Clark said nothing had been signed.
Meanwhile, Jamie Joseph has been spending some time coaching in the United States. He has been in Texas with Chiefs coach Dave Rennie.
