You've listed 4 pitchers out of probably about 40 guys that pitched in the WBC. I have no clue how they're doing, they may all be terrible too. But 4 pitchers' stat lines is proving nothing. Most of the pitchers that went deep into the WBC, don't pitch in the majors (Cuba/Japan), and there were only a few that got significant innings. Furthermore, we know the number of names doesn't prove anything. The whole world of understanding baseball injuries is still in the infancy stages. But it's also true that nobody has proven the WBC didn't cause any harm. It's like pitch count. Just because nobody has proven that 140 pitches is extremely dangerous doesn't mean a smart man would throw guys out there that long. I think there's enough evidence now, and there was enough concern going in, and there is enough logic behind the idea that pitching "meaningful" innings in early March, completely out of sync with normal preperation routines for pitchers, could be a bad thing and could have a negative effect on several pitchers. If 4 out of every 40 people who take a certain drug suffer severe complications, you wouldn't scoff at the correlation. Nobody is saying pitching in the WBC will hurt you. They are saying it's very possible that pitching in the WBC can hurt you, and there's not enough benefit (there's really no benefit actually, has anybody heard a thing about the WBC since the regular season started?) to justify that rather high risk. It didn't take years of studying pitchers to think that throwing in the WBC could be bad for guys, given the timing and the emotional tug of doing your best for your countrymen. It was a concern going in, and so far, multiple star pitchers are having bad starts to the season.