Youk has missed games due to back spasms each year, even when playing 1B. They knock him out for 3-5 games and then he is okay the rest of the way. They usually hit him a little after mid-season-- probably due to fatigue and dehydration.
Everyone is concerned about him playing 3B. I'm not. I don't think he is any more likely to suffer an injury at 3rd than 1st. I am concerned about his hip. That was the first of his injuries last year. That can be a chronic thing. I hope that he drops about 20 lbs to start the year. 240 is too much weight.