Marquez had finished Sepang MotoGP test day two plan when he crashed

The reigning world champion is riding below peak physical fitness due to a recent operation on a shoulder injury he picked up at last year's Malaysian Grand Prix, and said his shoulder felt worse than he expected on Friday.

After completing 37 laps on the first day, Marquez managed 47 on Saturday and cracked into the top 10 in ninth with a lap time 0.417 seconds off the pace.

As the session neared its conclusion, Marquez came off his Honda at the fast Turn 3 right-hander - though he admitted he was "going slow" through the corner having finished his programme for the day.

"The shoulder is coming better," Marquez said.

"I start the day with a lot of energy and I can ride the bike, but then I feel and I push, and immediately after the second two runs I started to drop [energy].

"It's normal. But the most important thing is it's not worse than yesterday.

"Today I achieved our target; yesterday was around 30 laps, today was 45. We did 47 and unfortunately when I was going to the box - I had already finished the day - I was on the dirty line.

"I don't know why, maybe because I was tired or something... of course if you check the corner you say, 'Woah, it's a fast corner' but I was [going] slow.

"So it was not a big crash.

"I need to be 200% concentrated because in that physical condition you need to be even more concentrated to avoid all these things."

Ducati's Andrea Dovizioso was the other high-profile crasher on Saturday, with the Italian coming off at Turn 6 in the afternoon and briefly bringing out a red flag.

Though he was able to return to action, he admitted he could not breathe after hitting the gravel and aggravated a pre-existing neck issue.

"[I] didn't push 100% in that moment, just opened the throttle at maximum angle in Turn 6 and I lost the front," he explained.

"Really small and easy crash. But, unfortunately I went to the gravel and it wasn't flat.

"So, I couldn't breathe. The problem is always with my neck. I hit it on top, now I'm really rigid.

"I hope tonight it won't become worse because it's always my characteristic."