The Back of the Giants’ Rotation Is Going Exactly As Expected

Heading into the offseason, pitching was the clear need for the San Francisco Giants. Even though the lineup has been a massive disappointment in 2026, that group was virtually set.

The rotation, on the other hand, looked barren. Logan Webb and Robbie Ray were one of the best one-two punches in baseball over the entirety of 2025. Landen Roupp was a slight question mark — simply because of a lack of innings in the past — but has been excellent to open 2026.

The last two spots were where Buster Posey would have some work to do. The Giants organization as a whole has been reluctant to spend big money on a starting pitcher for the majority of the last decade and that trend continued this winter.

Instead of trying to pay a Dylan Cease, Framber Valdez, Tatsuya Imai, or Ranger Saurez the lengthy deals they were looking for, they opted for two short-term options.

The first one came in the middle of December when Adrian Houser signed a two-year deal with the club. He was coming off a career rejuvenation with the White Sox and Rays and the Giants believed in some of the improvements he showed.

A few weeks later, we learned that the Giants had agreed to a one-year pact with Tyler Mahle. Mahle was coming off an exceptional year in terms of run prevention with the Rangers, but underlying numbers and consistent failure to stay healthy hindered his value on the free-agent market.

Many were under the belief that if these two were able to stay healthy for the majority of the season, San Francisco would be getting a bargain. However, Bay Area fans failed to realize a third outcome — them staying healthy and struggling to perform.

So far, that’s what has taken the place the majority of their outings.

Stats were taken prior to play on May 3.

Tyler Mahle

Mahle definitely has the higher ceiling of the two rotation additions and, so far, he has had the slightly better season. Unfortunately, similar to his entire career, it’s been as inconsistent as they come.

We’ve seen flashes that make him look like a true number three in a rotation. Just over a week ago, the righty struck out five in seven innings of shutout baseball against the best team in baseball — the Los Angeles Dodgers.

Two weeks before that, he tossed another shutout outing against the Phillies. This time, in 5 2/3 innings with six strikeouts.

After reading that, you may think Mahle’s season is off to a fine start. The problem is that in between those outings, he threw four innings against the Reds in which he allowed eight earned runs.

Just days ago, he gave up five earned against a Phillies offense that is bottom five in runs scored, batting average, on-base percentage, and weighted runs created plus.

This back and forth has been a theme throughout the 31-year-old’s entire career. In just under 130 innings in 2019, he held a 5.14 ERA and 4.66 FIP. Just one season later, he threw 180 innings with a 3.75 ERA and nearly identical 3.80 FIP.

As it currently stands, the Giants simply do not know which Tyler Mahle they are getting every fifth day, and that’s a problem. For a team struggling to string together wins under a rookie manager, it’s hard to hold a sense of confidence when you can’t rely on any sort of consistency from your Opening Day third starter.

Adrian Houser

For Adrian Houser, you can simply look at this numbers on the year and realize it’s been rough. In just over 30 innings, he holds a 7.12 ERA while striking out just 4.75 hitters per nine innings.

This is on the heels of a career year in which he had a 3.31 ERA in 125 innings. With a significant uptick in velocity across the board, San Francisco had belief in his ability to replicate the success.

This led to them handing out a multi-year deal for one of the riskier arms in free agency. Up to this point, he’s been killed by left-handed hitters, and that has led to a healthy amount of the big innings against him.

In 15.2 innings against lefties this year, hitters are slashing .395/.453/.737 with four home runs and eight walks. His first outing of the season against San Diego was relatively promising, but since then, it’s only been downhill.

As it currently stand, every fifth day is a scheduled loss. While it’s early and things could turn around, it’s been ugly for the 33-year-old, and the Giants are on the hook for two more years of this.

Where Do They Go From Here?

Luckily for the Giants, the top three of the rotation have been just fine. However, it’s hard to call yourself an organization driven by pitching and defense when these are your offseason additions.

If you’re not going to consistently develop above-average starting options, you have to be willing to pay for them.

The 2026 free-agent class had a plethora of arms that would have fit the Giants’ win-now roster and slid in perfectly behind Logan Webb and Robbie Ray.

One could make the argument that San Francisco even has better options in-house with names like Carson Whisenhunt, Trevor McDonald, and Blade Tidwell sitting in Triple-A. If things continue on this track, we could very well see one of them before the start of summer.

Buster Posey and Zack Minasian opted for the cheaper, more affordable options when it came to bolstering this rotation. Through the first month of the season, it’s clear San Francisco is getting what they paid for.