Padraig Harrington's bid to keep his European No 1 crown has been rocked by another neck injury.

The Dubliner had to seek on-course treatment at Royal Golf Dar es-Salam course in Rabat, where he will play through the pain barrier in this week's $600,000 Hassan II Trophy.

Set to go head to head with Justin Rose in the Volvo Masters next week, Harrington confessed that it might not be 100 percent fit until Saturday or Sunday.

And that's hardly ideal preparation for Valderrama, where he must finish in the top three and beat Rose to retain his Order of Merit title.

After feeling the right side of his neck "go" during the pro-am, Harrington explained: "In terms of my own preparation, hurting my neck is not so good.

"I don't expect to be 100 percent for the start of the event this week but hopefully it will ease itself out as the week goes along.

"I had just birdied the 15th hole and was feeling good about things and then ripped this lovely 5-wood down the 16th and something just went in my neck.

"No doubt something was lingering there but at the moment it is staying in my neck and has not gone into my shoulders and that is always a very positive sign for recovery."

Harrington immediately called for on-course treatment for the injury, which has plagued him throughout his career.

Regular physio Dale Richardson is not in Morocco, but the tournament organisers hastily laid a local expert to meet the Open champion in his hotel after his round.

Harrington added: "It usually takes 72-hours to heal but I should be fine because I actually scored better after I had injured my neck then before the injury.

"So the longer it goes, the more mobility I should get. But I don't think I will be 100 percent fully fit until Saturday or Sunday.

"I am not expecting miracles or for the injury to go away overnight. Luckily I have been doing a lot of exercises on that area lately, so much so that it hasn't flared-up that much."

Harrington will head to Valderrama next week in second place in the Order of Merit, €657 ahead of Rose and €217,952 behind leader Ernie Els.

Both men must finish third or better to overtake Els, who misses the Volvo Masters to play for appearance money in Singapore.

A trained accountant, Harrington has left it to his pregnant wife Caroline to work out the permutations ahead of next week's Volvo Masters test.

And he's happy with what he has to do after snatching the Order of Merit from Paul Casey thanks to a dramatic share of second place last season.

Harrington said: "My wife's worked out that I need to finish top-three and that's assuming Justin Rose doesn't finish ahead of me then I win the Order of Merit.

"It is very similar to the situation I faced when I went into the Volvo Masters last year but I came out with the European No 1 title so I have positive memories and hopefully I can do the same thing next week.

"If Justin and I are tied second, I would win. But we are both chasing Ernie."

Harrington could have cut the gap on Els in this week’s Mallorca Classic but opted not to play after missing the cut there last year.

He said: "I went to Majorca last year and in the week after winning the Dunhill but missed the cut and if I had of performed anywhere well in Pula last year, I would have looked to again playing this year.

"If I am to play my best golf next week at Valderrama, I need to be playing the week before and this Hassan II tournament is ideal. I really had forgotten how good the golf course is.”

The winner of the 35th edition of the Hassan II Trophy will take home $150,000 with Harrington joined in the field by former Open champions Mark O’Meara and Sandy Lyle.

Darren Clarke, Raphael Jacquelin, David Howell and Simon Dyson are also teeing it up.