Johnny Cueto Has Mild Flexor Strain, No Ligament Damage

9:15pm: Cueto will rest for a week before being reevaluated, per Pavlovic. The team expects him to return to the rotation this year, though there apparently will not be a specific timeline on that return until next week’s reassessment.

6:15pm: Pavolvic tweets that the further examination of Cueto’s injury revealed no damage to his ulnar collateral ligament. Henry Schulman of the San Francisco Chronicle tweets that Cueto has a mild flexor strain.

8:45am: Giants righty Johnny Cueto had been working back from a blister problem when he took the hill for a rehab start last night. But he ended up leaving halfway through his scheduled outing with forearm tightness, as Alex Pavlovic of NBC Sports Bay Area reports.

At this point, it’s too soon to know the prognosis. Cueto is set for a full examination by the team’s medical staff today, and it’s certainly possible that the problem isn’t indicative of a significant injury.

That said, forearm discomfort is often tied to other issues in and around the elbow joint, so the club will surely exercise caution with the veteran right-hander. Even in the best-case scenario, it seems likely that Cueto’s DL stint will be longer than had been anticipated as he and the club work to ensure that he’s at full health before pushing down on the gas pedal. And the longer he lays off, the more time that will be required to build him back up to the major league mound.

Just when Cueto will be back, then, isn’t at all clear at present. And that begins to raise new questions about the status of his opt-out decision at season’s end. Cueto will be deciding between a return to the free-agent market — this time with a possible qualifying offer weighing him with some draft compensation — and a return to San Francisco for at least four more years and a guaranteed $84MM. (Either way, Cueto will also be entitled to $4MM more on his signing bonus as well as a $5MM buyout of a $22MM club option for 2022.)

The injury illustrates just why it was always going to be tough for the Giants to trade Cueto this summer. Even assuming away the possibility of a major injury, the uncertainty of Cueto’s intentions left suitors unsure whether they’d be adding a rental or a major long-term commitment. As it stands, that’s just what San Francisco is wondering — though, fortunately, the team is still interested in employing the veteran (assuming he’s healthy) into the future.

Even before the blister and forearm issues arose, there were growing questions as to whether Cueto would stay or go. The 31-year-old had thrown 115 2/3 innings over 19 starts on the year before hitting the DL, but sports an uncharacteristic 4.59 ERA. He does carry a fairly typical 8.0 K/9 and a 10.6% swinging-strike rate that’s higher than his career average. And he has not sported

While there were no major red flags prior to Cueto’s DL stint, there were signs of some decline. He has permitted more hard contact than ever while coughing up 1.48 homers per nine. His groundball rate has fallen to below forty percent after topping fifty last year, he has walked more than three batters per nine (his highest rate since 2009), and he’s averaging just under 92 mph with his fastball for the first time in his career.