Youk is going down pretty easily these days especially to the slider from RH pitchers and his RH/LH splits have been changing gradually over the years from a hitter that was equally dangerous facing LH or RH pitchers to a hitter that on a progressive basis has really been struggling against RH pitchers and has continued at about what has become his usual pace against LH pitchers. This is not that rare. Baseball players do not age or change serially.
The biggest concern about Youk is that he appears really vulnerable to being set up by RH pitchers for low, outer edge pitches and does not appear to be able to see that slider from RH pitchers at all. If he was meat for a slider throughout his career, we would have seen that long ago. He has SO 20 times in 61 AB and has had 5 BB in 65 PA. 16 of the SO have come against RH pitchers.
Not sure what his future is going to be. It is not like he can go into remedial slider training and not sure what he can do to recover whatever it is that he has lost. The fact is his LH/RH splits have been undergoing progressive change for the past few seasons not just this season. This is so much the case that in his younger days there were actually some instances when he had more success against RH pitchers than LH pitchers. That is long in the past now with this year so far, really telling as he is not even making contact with RH pitchers.