Trevor McDonald to undergo Tommy John surgery, likely out for all of 2027

What happened

Giants starter Trevor McDonald will undergo Tommy John surgery, manager Tony Vitello said Tuesday, per Maria Guardado of MLB.com. The UCL reconstruction carries a 14-16 month recovery timeline that would likely keep McDonald off the mound for all of 2027.

The news, while unwelcome, was not entirely unexpected. McDonald was placed on the injured list last week with what was described as a moderate UCL sprain, and surgery was the feared outcome at the time of that placement. The formal word on the procedure arrived Tuesday via Vitello.

Why it matters

McDonald had held a rotation spot in San Francisco since early May, making this his first extended run in the big leagues. He pitched well in the early portion of that stretch before tailing off in the weeks leading up to the injury. He finishes the season with a 5.12 ERA across 70 1/3 innings — a line that tells part of the story, though the ground-ball and strikeout figures add texture to what kind of pitcher he was working to become at this level.

For a Giants club that is 65-97 and already eliminated from both the division race and the Wild Card race, the immediate competitive cost of losing McDonald is modest. The longer shadow falls on 2027 and beyond. A 25-year-old starter who had just established himself in a major-league rotation is now looking at a full calendar year away from game action, with a return timeline that pushes well into next season at the earliest.

Tommy John surgery — formally, UCL reconstruction — has become one of the more familiar procedures in professional baseball, in the sense that the medical community has refined both the operation and the rehabilitation protocols considerably over the decades. "Familiar," of course, is a relative term when the recovery window spans more than a year. The 14-16 month range Vitello cited is consistent with how the league generally discusses the procedure's timeline, though individual recoveries vary and no timetable should be treated as a guarantee.

The numbers

McDonald's season line — a 5.12 ERA across 70 1/3 innings — reflects a pitcher who was still finding his footing at the major-league level. The more interesting figures are the peripheral ones. His ground-ball rate of 55.2% is a legitimately strong number, the kind that suggests his stuff plays down in the zone and that he was generating weak contact even when results weren't always clean. A ground-ball rate in that range is not something a pitching staff discards lightly.

The 18.4% strikeout percentage is the counterweight — modest by modern standards, and a figure that leaves a ground-ball-heavy approach with little margin for error when the ball does get in the air or when command wavers. The combination of those two numbers sketches a pitcher whose profile was still developing: the ground-ball tendency is a real asset, but the strikeout rate would need to grow for the overall package to hold up consistently at the big-league level.

He was 25 years old and in his first extended major-league season. Both of those facts matter when projecting what comes after the recovery.

Where the club stands

The Giants are 65-97, sitting fourth in the NL West, 35 games back in the division, and ranked 11th in the Wild Card picture at 23.0 games relative to the cut line. They have dropped five consecutive games. The rotation assignments ahead are immediate and practical: Logan Webb starts Wednesday against the Milwaukee Brewers at Oracle Park, Robbie Ray takes the ball Thursday at Petco Park against the San Diego Padres, and Carson Whisenhunt follows Friday in the second game of that San Diego series.

McDonald's absence does not change those assignments, but it does clarify the depth picture for a club already working through a difficult season. The 40-man roster and the 60-day injured list are the relevant mechanical levers here — a pitcher undergoing Tommy John surgery would typically be transferred to the 60-day IL, which removes him from the 40-man count and creates roster flexibility. Whether the Giants have made or will make that move was not specified in Tuesday's update.

What we don't know yet

The Giants have not announced the timing of the procedure itself, nor have they specified a target return date beyond the general 14-16 month recovery window Vitello cited. That range, if it begins around the time of surgery, would point toward a return sometime in the fall of 2027 at the earliest — which is why the characterization that he would likely miss all of 2027 is the operative framing, per the report.

There is also a separate and genuinely strange subplot developing in the Giants' injury room. Vitello provided an update Tuesday on outfielder Harrison Bader, who has been dealing with plantar fasciitis in his left foot since late May. Per Vitello's Tuesday remarks, Bader sustained a reinjury to that foot over the weekend — the circumstances of which involved a scooter, because 2026 is not done with the San Francisco Giants — and was sent for imaging on Tuesday. The team had not announced the results of that testing as of Tuesday's update. The nature of the reinjury, the severity, and any updated timeline for Bader are all outstanding questions.

What to watch

The most immediate question is when the Giants formally announce the roster move that accompanies McDonald's surgery — specifically whether he is transferred to the 60-day IL, which would open a 40-man spot. For a club in the Giants' current position, that kind of roster flexibility carries real value as they navigate the remainder of the season and begin planning for 2027.

On the Bader front, the imaging results that were pending Tuesday will determine whether his situation represents a setback within an existing recovery or something more significant. A reinjury of any kind complicates whatever timeline the club had been working from, and the full picture there remains incomplete.

For McDonald specifically, the watch item is longer-range: a 25-year-old with a 55.2% ground-ball rate and a developing profile is exactly the kind of pitcher a club wants to see come back healthy and with a full offseason of preparation behind him. The 14-16 month window is the frame. What he looks like on the other side of it is the question that won't have an answer for a long time.