Rins crashed in qualifying for the Spanish GP in Jerez last week and had to cancel the race due to an injury, but was declared fit to drive on Thursday.
He only completed eight rounds in FP1 without the use of painkillers and admits that he was in “a lot more pain” than he expected after the session.
He managed 16 laps in FP2 and a best lap of 1: 39.101 minutes to finish the day 21st and last on the combined timesheets after being anesthetized that afternoon.
“It’s been a tough day for me, a painful day,” said Rins. “I had a lot of pain on the bike.
“Before the start I thought I was going to be in a bit of pain, but I can drive well. But after the session I saw that it was impossible. I was in a lot more pain than I expected.
“Anyway, we have to keep fighting and working, FP2 was much better than FP1.
“I didn’t use anesthetic in FP1, but I used some in FP2 to see if we could relieve the pain. There was a little less pain, but not enough. “
Rins says he doesn’t have “enough strength” in his shoulder at the moment and will skip the rest of the weekend if it still poses a risk to him and the drivers on the track on Saturday.
“The positive thing is that after FP1 and FP2 the shoulder doesn’t look like [like it has] a lot of inflammation, ”he added.
“That means I don’t risk the tendons. Let’s see tomorrow.
“I definitely have to feel good on the bike and as soon as I see that I don’t have enough power, I will stop because it is risky for me and the other riders.”
LCR Honda’s Cal Crutchlow also returned to Jerez on Friday after breaking his left wrist while warming up in a fall last Sunday.
Crutchlow completed 24 laps throughout the day in 20th place on the combined timesheets and said he showed “it’s possible to ride a bike” but admits that his feeling is “a little strange”.
“I think I showed this weekend that it was possible to ride a bike,” said Crutchlow.
“My feeling on the bike is a little weird, I don’t have that much wrist pain, but when I am in pain I just try to ride around as best I can.
“I have the feeling that my condition on the bike is not optimal after the crash last week, but we will continue to work over the weekend to make me feel comfortable and good for the rest of the race weekend.
“I think the surgeon Dr [Xavier] Me and the doctors did a good job, as well as keeping the ice on my wrist and doing my best to keep the inflammation down.
“[I’ll just] Grit your teeth and get on with the bike. “
Reigning world champion Marc Marquez will ride on Saturday after being deemed fit to drive on Thursday after surgery on his broken right arm on Tuesday.