Nats face rehab decision on Rosenthal at week's end

Trevor Rosenthal is slated to make another rehab appearance tonight for Double-A Harrisburg, once again trying to put together the kind of clean inning of relief that convinces the Nationals he can be trusted to return to the big league bullpen again.

This has been going on for nearly four weeks now, but it cannot go on long enough to reach a fifth week. The Nats have managed to delay this decision as long as they can, but they're about to be forced into making it, one way or the other.

MLB's collective bargaining agreement allows for pitchers on the injured list to spend up to 30 days on a minor league rehab assignment. (Position players are capped at 20 days.) At the end of the 30-day stint, the club is required either to activate the player or shut him down with either a new injury or recurrence of the previous injury, with approval of the Commissioner's Office.

Rosenthal began his assignment with Harrisburg on May 11. That makes Sunday his 30th and final day of eligibility.

The dilemma for the Nationals: Rosenthal's officially on the IL with a viral infection, an ailment that has long since been resolved. They aren't going to be able to claim it has returned. So in order to get approval for another rehab assignment, they're going to have to prove the right-hander has suffered a new injury.

Rosenthal has insisted all along he feels great. Which means his struggles on the mound are either mechanical or mental. Both the pitcher and the organization have insisted all along it's the former, not the latter.

Whatever the case, Rosenthal has not been able to pitch effectively beyond a couple of clean outings. In eight total appearances, he has allowed four runs and six hits in 7 1/3 innings, with seven walks, three hit batters and only 84 of 164 pitches thrown for strikes.

If he has an efficient outing tonight, Rosenthal might get an opportunity to return Wednesday and pitch back-to-back games for the first time. Nationals manager Davey Martinez has said that's a necessary prerequisite before the 29-year-old can rejoin the big league bullpen.

The Nationals signed Rosenthal (who missed 18 months recovering from Tommy John surgery) early in the offseason to a contract that guarantees him $8 million and includes a $10 mutual option for 2020, then watched the former All-Star closer implode when the regular season began. In seven games, he allowed 12 runs and seven hits in only three innings, walking nine, hitting three batters and issuing five wild pitches.

They've got a few more days to decide if they're willing to give him another chance to pitch for them and turn the narrative around.

Note: Ryan Zimmerman resumed baseball activities today and will accompany the Nationals on this weekend's trip to San Diego, where he will attempt to begin running again. Zimmerman has been on the IL since April 28 with plantar fasciitis in his right foot, and though he made some progress he was shut down last week with a recurrence of pain when he tried to run.