The most predictive thing for TJ is being a pitcher. The next most predictive things are previous elbow issues (book TJ the moment you hear anything about forearm/elbow tightness/soreness/tingling), and sudden increases in velocity.
This is why folks shouldn't be so scared to deal these FV 50 arms for immediate help when a team is in contention. This is also why it is foolish to guarantee any cash to any pitcher for more than 2-3 years at a time beyond their 20s, at which point they are both declining and still a massive injury risk.
Smart GMs obviously know this, but the pressure to win now while they have a job outweighs the consequences 5+ years from now when they could very well be out of a job anyways.