I'm not sure how a BABIP of .306 could be construed as a warning sign for a fast player with a strong LD%. If I had to put money on it, I'd bet that it gets higher, not lower.
27 years old, injury free, normal BABIP, nothing out of line with minor league stats. Common sense would indicate a similar season if his fielding numbers were accurate, but we won't know that for a couple more years.
Like who? Navarro and Flowers were pretty much the only available catches that are better than Thole. Shapiro is smart enough to know that the solid D is what matters, not 100 at-bats or whatever. Finding some additional depth would be nice, however.
Thole projects for 0.1 WAR in 98 at-bats. His career wOBA is better than 11 teams got from their catchers last year, including the Mets and Cardinals.
You have unrealistic expectations of a backup catcher.
He's 27 years of age and has averaged nearly 7 BsR per 600 PA for his career. He's been even better in the past 2 seasons. The reason to project a precipitous decline eludes me. The number of infield hits he had was right in line with career norms.
For you to conclude that his hitting will suffer at the RC after a small 50 game sample where he hit .319 is ill advised in my opinion.