By Nick Mulvenney

BEIJING, CHINA (Reuters) - Michael Schumacher's abortive decision to return to Formula One last season as a replacement for the injured Felipe Massa was "emotional not rational", the seven-times world champion said on Tuesday.

Brazilian Massa sustained serious head injuries in qualifying for the Hungarian Grand Prix in July and missed the rest of the season leaving a vacant seat in the Ferrari team.

Schumacher, who retired at the end of 2006, was ultimately unable to take up the drive because of a neck injury.

"It wasn't really a rational decision, it was an emotional decision, which, at the time, I thought 'why not, it's part-time, it could be funny,'" the 40-year-old told reporters at the Bird's Nest stadium, where he was taking part in the Race of Champions tournament.

Schumacher said he had weighed up the pros and cons of making a comeback after a discussion with Ferrari boss Luca Di Montezemolo.

"Having the meeting with him (Di Montezemolo) I looked at all the points, in particular that it was Felipe, who is like a brother to me. Part of the reason I retired was to hand over the car to him because he deserved to stay in a team with a top car," said the German.

"So taking the fact that it was him, having the accident, having to suffer, it was very easy to convince myself, so I finally said 'yes, I will try'."

Despite abandoning the comeback, rumours persist that he could still return if Massa has not recovered from his injuries by the start of next season.

Asked whether he would return to the sport he dominated for so long, he said: "Right now, no."

Schumacher was out to defend the Race of Champions "Nations Cup" title with fellow German and 2009 Formula One runner up Sebastian Vettel on Tuesday.