Which of the following types of cases does the system arbitrator handle?

The correct choice is the one that highlights the range of matters the system arbitrator is responsible for in the context of the NFL. Specifically, the system arbitrator oversees free agency issues, salary cap regulations, and matters related to franchise tags. This function is essential for maintaining a level playing field within the league and ensuring that all teams adhere to the established rules and policies regarding player transactions and financial allocations.

Free agency involves the process where players who are not under contract can sign with any team, while salary cap regulations ensure that teams do not spend beyond a certain limit to promote competitive balance. Franchise tags allow teams to retain players for an additional year under a specific contract set by the league, providing teams with leverage over their key players.

Each of the other options is more limited in scope. For instance, focusing solely on contract disputes or only on player grievances would not encompass the broader responsibilities of the system arbitrator. Limiting the arbitrator's purview to injury-related claims excludes the essential aspects of player movement and financial management that are central to team operations. Thus, the choice that encompasses these critical components of the NFL's operational framework is the one that is correct.