MotoGP title leader Valentino Rossi says it is impossible to know the significance of rival Jorge Lorenzo's shoulder injury until Friday's opening practice at Motegi.
Lorenzo hurt his left shoulder when he fell while training on a minibike, less than a week after reducing team-mate Rossi's lead to 14 points with victory at Aragon.
The Spaniard says X-rays have ruled out any fractures, or the need for surgery, but admits to feeling some pain.
“Sincerely for me it is impossible to know [how much the injury will affect Lorenzo],” said Rossi, no stranger to shoulder injuries of his own in the past. “Also because I think that Jorge does not know yet.
“Have to wait for his feeling when he rides the bike tomorrow morning because the shoulder is always difficult, a big pain, but depends on if [the pain] is for normal life or riding the motorcycle. Because sometimes you have pain just doing easy things, but on the motorcycle you have less problems.
“I think it is impossible to say. He has to see tomorrow on the bike but, you know, one time Jorge raced straight after putting screws for a broken collarbone [Assen 2013], so anyway he is strong and we have to think of us and try to make the maximum to be competitive on Sunday.”
Tied with Lorenzo at the top of the standings after Brno, Rossi then pulled away again in the rain at Silverstone and Misano.
That put the Italian on the brink of building a psychological 25-point championship lead, but Lorenzo struck back at Aragon, where Rossi lost nine points after a spirited fight from Dani Pedrosa handed second to the Honda rider.
All of which means after 14 rounds Rossi leads Lorenzo by 14 points.
“Is very tough. it is still 100% open,” Rossi declared of the title battle. “Now have the last four races and for sure will be most difficult moment because everything is tighter and closer.
"We have three races in a row, I like a lot the racetracks and starting from Motegi I won just two times in my career but apart from that I did some good races, on the podium, also last year.
“Usually Jorge is very, very strong in this track. He won here for the last two years, but we just have to give the maximum and try the best.”
One of the keys to this weekend will be maximising braking performance for the stop-go Motegi layout.
“This track is the most demanding for braking,” Rossi confirmed. “For the bikes, but also for the riders because you have a lot of force to slow down and a lot of hard braking [areas] during each lap.
“But have also some good corners. I like the layout and usually the grip is very good. So you make a lot of lean angle in the corners. As always we will try to make good work on the setting to be strong in braking and we will see.”
Aside from Lorenzo's injury another unknown factory is the weather, with forecasts suggesting a strong chance of rain on Sunday. Given his form at Silverstone and Misano, most would expect rain to favour the seven time MotoGP champion.
“My team said to me [about] this,” Rossi said of the weather. “I don't know if I have to say happy or not. First of all, all the riders more or less, we hope it is dry. You never know if you are competitive or not in the rain. It depends very much on the setting. Sincerely I hope for the dry race.”
While fans are yet to see a true head-to-head battle between Rossi and Lorenzo this year, Motegi was the scene of one of their most famous clashes in 2010.
Rossi - out of the championship battle after a broken leg at Mugello - got the better of title leader Lorenzo for third place after some hard passes, which resulted in a talking to from Yamaha.
“2010 was a great battle! Also with a little bit of problem later,” Rossi confirmed. “We did a lot of overtaking and was very hard. I remember it in a good way but I don't know if it will happen another time.
“Like I've said, usually our way to race is quite different. When Jorge is very strong, he starts the race very strong and it is difficult to go with him. For this reason our races are a bit different.”
Lorenzo is not the only MotoGP star carrying an injury with reigning champion Marc Marquez undergoing surgery for a hand fracture while training on a mountain bike last week.