What happened: Washington Nationals pitching prospect Alejandro Rosario has returned to throwing off a mound for the first time since 2024 following Tommy John surgery to repair a torn UCL. Rosario missed the entire 2025 campaign after his procedure was delayed and did not pitch in 2026 while completing his rehabilitation.

Why it matters: Rosario represents the highest-ceiling arm in the five-prospect package Washington acquired in the MacKenzie Gore trade last offseason, while the other four prospects in the deal have already debuted in the organization. Now healthy enough to resume mound work, the hard-throwing right-hander profiles as either a multi-inning bullpen option while rebuilding his workload or a long-term rotation piece along a trajectory similar to Cade Cavalli.

What to watch: Washington must decide this offseason whether to protect Rosario from the Rule 5 Draft ahead of his 25th birthday in January. His spring progression will dictate whether the Nationals deploy him in relief to manage his innings or stretch him out as a starter for the upcoming season.