Erik Kratz’ hair is thinning, which is a good thing. If he had a thick head of hair he’d be pulling it out in clumps. Kratz appears to be in the driver’s seat as the Blue Jays No. 2 catcher, squatting behind Dioner Navarro in the pecking order. When it comes to catching R.A. Dickey’s elusive knuckleball, though, Kratz is No. 1. This spring, due to his more dangerous bat, the Jays decided to team Kratz with Dickey to see if he is up to the task. If he isn’t, if he was boxing balls all over the place and has balls zoom by him at a prodigious rate, they would turn the duties back over to Josh Thole, who was Dickey’s personal catcher for the second half of last season and his time with the New York Mets. Dickey was on the mound Saturday in a minor-league game against the Phillies triple-A farm team, which meant that back of the plate sat Kratz. This day there were no passed balls and just one that ticked off his glove and made it back to the screen. In his past (the 2005 season) Kratz has had limited experience with a knuckleball pitcher but catching Dickey is something different altogether. He throws a much harder one and he works at an exhausting pace. It makes for a draining day in every which way. “For sure and that’s what I’ve heard from other guys that I’ve talked to who have caught him,” Kratz said Saturday. “It’s definitely mentally draining. It’s definitely mentally taxing.” It’s a gauntlet that has been thrown down and the 33-year-old native of Harrisonburg, Va., is up to the task. “Like I said, it’s a cool challenge, it really is,” Kratz said. “Any athlete, any competitor will say that the competition, the effort level is something ... well, you’re never want to be somebody that’s ‘Well, I didn’t quite give it all I had today.’ “In a sense you have to kind of just relax and let the game come to you, which you have to do normally, but as a catcher you kind of have to have that energy out on the field that everyone’s looking at you — everyone thinks well, everyone’s looking at the pitcher — well, the players at the field are looking at the catcher and if you have a bad energy catcher you have a bad energy team in my opinion. The best teams have guys who are high energy, you look at them and they are in every play, they’re ready to go.