Kobe Kobelco Steelers flyhalf Dan Carter revealed Tuesday he will undergo neck surgery and is unable to rejoin his former club Racing 92 to finish out the French first-division season as he had planned.

"I'm incredibly disappointed that I won't be able to join Racing for the rest of their season. During some routine medical checks, we discovered that I have an issue with my neck that needs to be addressed," Carter said on Instagram after failing a medical.

The Steelers had announced Carter would return to Japan to play for Kobe after the Top 14 season ends. The next Top League season will not kick off until January 2020, following a break after the 2019 Rugby World Cup wraps up in November.

"I'm really grateful to Kobe, who were supportive in allowing me to temporarily return to Paris. Now, the focus switches to fixing the issue, (surgery and rehab)," Carter said.

The 37-year-old was named the 2018-19 Top League MVP and Top Kicker in his first season in Japan after helping the Steelers win their first league title since 2003-04.

He signed with Kobe at the end of the 2017-18 Northern Hemisphere season to be closer to his native New Zealand and said upon joining he was considering ending his career in Japan after playing for two years.