Giants select LHP Cesar Perdomo as active rosters expand to 28

What happened

The San Francisco Giants announced they have selected the contract of left-hander Cesar Perdomo from Triple-A Sacramento and recalled catcher Zach Morgan, also from Triple-A Sacramento, as active rosters expanded from 26 to 28 players. To clear a 40-man roster spot for Perdomo, right-hander Adrian Houser was transferred to the 60-day injured list. Prior to the club's announcement, Justice delos Santos of the Mercury News noted that both Morgan and Perdomo already had lockers in the clubhouse — the kind of detail that tends to get out before the paperwork does.

The two additions represent the full scope of San Francisco's expansion moves. The club used both newly available spots on Perdomo and Morgan rather than spreading them across a longer list of September names.

Why it matters

Perdomo, 24, joined the organization as an international amateur out of Venezuela in 2021 and has been climbing the system since. The 2026 season marked his arrival at the upper levels: he split time between Double-A and Triple-A, and the Giants' decision to select his contract — rather than simply recall him on an existing 40-man spot — means he is now on the 40-man roster for the first time. That distinction carries weight beyond September. Under general league rules, 40-man status affects Rule 5 Draft eligibility, and adding a player to that list is a signal that the organization wants to protect him from being selected by another club in the offseason draft.

The Houser transfer to the 60-day injured list is the mechanism that made the roster math work. The 60-day IL removes a player from the 40-man count entirely, which is what created the opening for Perdomo's addition. Houser's placement there is the transaction that enabled the selection, not a separate piece of news — though the nature of his injury has not been disclosed publicly.

The numbers

Perdomo's 2026 season line offers a reasonable portrait of what the Giants are bringing to the big-league roster. Across 24 appearances — 22 of them officially starts — he threw 120 innings and posted a 4.43 ERA. He struck out 24.6% of batters faced while issuing walks at an 8.3% clip.

Those two rates together sketch a pitcher who misses bats at a solid clip but has had to work around some free passes — a combination that tends to make pitch efficiency and sequencing the variables worth watching as he steps up in competition. Throwing 120 innings across Double-A and Triple-A in a single season is also a meaningful workload marker for a 24-year-old who finished last year at High-A; the Giants have been stretching him out, and the contract selection suggests they liked what they saw.

Baseball America currently lists Perdomo among the Giants' prospects, per MLB Trade Rumors, though the specific ranking was not included in the materials surrounding the announcement.

Where the club stands

San Francisco enters September at 59-84 (.413), sitting fourth in the NL West and 26 games back in the division — a race the club has already been eliminated from. In the broader National League Wild Card picture, the Giants rank 11th, 16.0 games relative to the cut line. They arrive at this roster expansion on a one-game winning streak, which is the kind of streak that earns a polite nod and not much else at this point in the standings.

The schedule ahead does not offer a gentle introduction to the big leagues for anyone making a debut. The Giants open September with a three-game series at PNC Park against the Pittsburgh Pirates: Logan Webb faces Paul Skenes on Tuesday, Landen Roupp is lined up against Bubba Chandler on Wednesday, and Blade Tidwell draws Lake Bachar on Thursday. Whether Perdomo factors into that series — or whether he is being held back for later in the month — is not yet known.

Is Perdomo in line to pitch in Pittsburgh?

Nothing in the club's announcement or in Justice delos Santos's Mercury News reporting addresses Perdomo's immediate role or when he might make his first appearance. The Giants have not indicated whether he is expected to be used as a starter, a bulk-innings option, or in relief during the Pittsburgh series. His 2026 workload — 22 starts across Double-A and Triple-A — suggests the organization has been developing him as a starter, but how that translates to a September big-league role on a 59-84 club is an open question the roster move itself does not answer.

What we don't know yet

The nature of Adrian Houser's injury has not been disclosed in the announcement or in the reporting around these moves. His transfer to the 60-day injured list is part of the club's announcement, but no diagnosis or timetable has been attached to it publicly.

It is also unclear what role Zach Morgan will play behind the plate for the remainder of the season, or how the catching situation shakes out with the roster now at 28. The announcement covers his recall from Triple-A Sacramento but does not address playing time or depth-chart positioning.

Perdomo's specific ranking on Baseball America's Giants prospect list was referenced in the MLB Trade Rumors report but the sentence was not completed — the ranking figure is not available from the materials at hand.

What to watch

The most straightforward thing to monitor is when Perdomo actually takes the mound in a Giants uniform and in what capacity. A 24-year-old left-hander with 120 innings of upper-minors work making his major-league debut in a low-stakes September for a rebuilding club is exactly the kind of audition that shapes offseason roster decisions — both for the player's 40-man standing and for how the organization frames his development arc going forward.

The Houser situation is worth a secondary watch. A 60-day IL placement this late in the season effectively ends his 2026 campaign, and any update on the nature of that injury would clarify whether his absence is a short-term setback or something that carries into offseason planning.

More broadly, the Giants' use of both expansion spots on a catching depth piece and a pitching prospect — rather than, say, a veteran arm or a positional utility option — says something about where the organization is directing its attention in the final weeks of a difficult season. Whether Perdomo rewards that attention with a few strong outings is the storyline to follow as the calendar turns.