Wearable monitors allow for this and have proven to reliably assess pitching workload, kinematics, and kinetics.  Newer technology, such as wearable monitors, may provide an alternative and allow for assessment during actual competition.
Wearable monitors
Three-dimensional motion analysis in a laboratory setting is most commonly used to evaluate the throwing motion, but it does not allow for assessment in real game scenarios.  Classically, three-dimensional motion analysis has been used to evaluate throwing mechanics and is considered the gold standard. 
Three-dimensional motion analysis