Depends what you want to understand.
If the question is, “Do i need to go deeper in order to say that Sabathia is having a shitty year so far?”, the answer is probably “No.” While many statisticians believe that WHIP is often a better measure of pitching than ERA, the fact is that an ERA of 13+ is so high that it’s a pretty damn good indication of bad pitching. Also, Sabathia’s WHIP so far this year is up at 2.56, exactly twice as high as his career average.
The wins thing, on the other hand, is really an almost pointless statistic. Once we know that he has an ERA of 13.57 and a WHIP of 2.56, we don’t even need the wins stat. If, by some miracle, the Indians had managed to score 10 runs for Sabathia in each of his 4 starts, he might be 4-0 right now, but his pitching would still be crap.
Look at Roger Clemens for the Astros in 2005 and 2006. His W-L records in those seasons were 13-8 and 7-6, which is not exactly typical Cy Young figures. But his ERA/WHIP figures in those two seasons were 1.87/1.01 (2005) and 2.30/1.04 (2006). He was absolutely killing the opposition, but when he pitched the Astros were hitting like a bunch of little leaguers. I think he got some of the worst run support in Major League history for much of those two seasons. Didn’t change the fact that he was pitching awesomely.
Also, getting back to Sabathia, what questions you ask depend on what you want to know. Sure, an ERA of 13.57 is enough to tell you that he has pitched poorly in his 4 starts this year, but ideally you might also want to know what this means for the future. So you need to ask, for example, whether a 4-game stretch is a large enough sample size to draw any reasonable conclusions about his longer-term form.
Also, you need to move beyond the stats (amazingly, stats geeks are actually able to do this!) and look at Sabathia himself. Has he put on, or lost weight? Have his mechanics changed in some way that might be contributing to his poor pitching? Is he suffering from some sort of chronic injury, or perhaps from short-term pain or illness? If there is something that is affecting him, and that seems to be temporary, it could be that his slump will also be temporary. And if everything seems fine, but he’s still pitching poorly, it might be a sign of long-term problems for him, and for Indians fans.