Although they have not thrown an MLB pitch in 2023, Caleb Thielbar threw 4,132 pitches that were tracked by the PITCHf/x system between 2013 and 2022, including pitches thrown in the MLB Regular Season and Spring Training. In 2022, they relied primarily on their Fourseam Fastball (93mph), Slider (81mph) and Curve (73mph). He also rarely threw a Splitter (83mph).
In 2022, compared to other LHP:
His fourseam fastball generates an extremely high number of swings & misses compared to other pitchers' fourseamers, is straight as an arrow, results in more flyballs compared to other pitchers' fourseamers, has slightly above average velo and has some added backspin. His slider sweeps across the zone, results in somewhat more flyballs compared to other pitchers' sliders and has some two-plane movement. His curve has an exceptional bite, has below average velo and has slight glove-side movement. His splitter (take this with a grain of salt because he's only thrown 16 of them in 2022) is basically never swung at and missed compared to other pitchers' splitters, has surprising cut action, is an extreme flyball pitch compared to other pitchers' splitters and has movement that suggests a lot of backspin.