True, but I'm not as worried about it as some. First, he'll be another year removed from surgery. Second, it's not just arm strength that goes into it. He had limited action catching last season. I wouldn't be surprised if all of his abilities behind the plate would take some time to get back mechanically and physically. Even if his arm isn't as strong as it once was, his ability to get the ball out of his hand quicker and get into throwing position faster will improve with time behind the plate. Third, small sample warning lights should be going off. Throwing out runners is not just on the catcher. When dealing with a large data set a better caught stealing % is more reliable. That weeds out the significance of pitchers who don't hold runners well, or an unusually high number of great base stealers who can make a smaller sample size look different than the catcher's actual ability.
I'm not trying to say he's ready now nor downplaying what shoulder surgery has on caught stealing rates. I'm just not that worried he's no longer capable of being a good overall catcher when his entire goal was to get back up to speed as a catcher. At least not based on a half season's worth of caught stealing rates.