Ducati's Nicky Hayden struggled to make progress on day two of the Sepang MotoGP tests in Malaysia after being hampered by his injured left shoulder.
The 2006 world champion only managed to complete 16 laps before he was forced to call it a day as the pain in his shoulder, which he injured during a pre-season training crash, became too much.
Hayden's best lap of 2m2.352s was the 10th fastest lap overall and following his decision to pull in, test rider Franco Battaini took over on the Desmosedici GP12.
“I was okay when I first went out this morning, and on my second lap I managed to make a pretty decent step from yesterday.
"After that I lost strength in the shoulder and wasn't really able to ride fast or consistently enough to test much,” said a disappointed Hayden.
“I'm okay under braking because I can lock my shoulder out, but when the bike shakes I don't have enough strength to hold on. I didn't want to crash and cause bigger problems, so I just decided to chill out.
“It's a bit of a bummer, but that's how it goes sometimes. They've done a great job with the new bike, and you can see just from looking at it that it's really slick.
“I just wish I could ride it closer to the edge and really see what it does and how it reacts to changes. Maybe I'll do a few more exits tomorrow, but that's about it.”
Hayden's team-mate, Valentino Rossi, was seventh quickest with a time of 2m1.886s.