Why the Mariners Signed Backup Catcher Andrew Knizner

Why the Mariners Targeted Andrew Knizner

Defense First: Framing

What the Mariners have targeted is dependability. Knizner is a 30-year-old veteran with uninspiring offensive numbers. He recently changed his stance, adopting the widely preferred one-knee, which led to improved defensive statistics. He did not allow a single passed ball across 234 innings, and his framing numbers have increased significantly since changing to this one-knee stance.

Knizner moved from consistently negative framing marks earlier in his career to positive framing runs in both 2024 and 2025. His work at the bottom of the zone stands out. The contrast is sharp when compared to their backup catcher in 2025, Mitch Garver. Since 2024, Knizner has converted a higher percentage of borderline pitches into called strikes, posting positive framing runs (+3) compared to Garver’s negative mark (–6), particularly on pitches at the bottom edge of the zone. While Garver has more power and upside offensively, particularly against lefties. Statistically, Knizner is a surer bet defensively. This shows how much the Mariners value catchers who can convert borderline pitches into strikes, even with ABS being implemented in 2026.

Offensive Trade-Off: Discipline Over Power

With the bat, Knizner looks pretty underwhelming with 73 wRC+, 33 points below league average, and all power statistics declining in recent years. From 2024, his hard-hit rate is down 11%, barrel rate down 3%, average exit velo is down 3 mph, as well as both slugging and xSLG. This profile would be concerning for an everyday starter, but as a one-year backup catcher, it remains serviceable, particularly given the likely reasons behind the power decline.

As his slugging production has fallen, his contact and plate-discipline numbers have improved, reflecting a conscious effort to prioritize swing decisions and consistent contact. In just one season, he went from striking out 23.7% of the time in 2024 to 11.4% in 2025, well below the league average of 22%. His walk rate went up from 1.1% to 8.0% in 2025, and lowered his whiff rate by 7.4%. This, paired with a rising in-zone swing % and declining out-of-zone swing %, shows an incredible improvement in plate discipline. His wOBA and xwOBA also went up from unusable to at least serviceable in 2025.

This signals potentially what they are looking for from fringe players in 2026. Difficult, lengthy at-bats drive up pitch counts and create more opportunities for their star players to cash in. They are looking for good process over production, and discipline over power, with low-variance at-bats. For someone like a backup catcher who is there only to give relief to your best player, they are valuing predictability and defensive framing. This was all evident in the Mariners’ interest in signing Knizner as their backup catcher.

What This Signing Tells Us About the Mariners

The backup catcher market this offseason has already shown how quickly costs can escalate. What his contract also tells us is that they saw Danny Jansen average $7 million a year and felt that was way too rich for what they are looking for. With Luke Stevenson also drafted in the first round, this contract does not block him from playing time in 2027 or 2028. If it so happens, he shows he is ready to make the jump at that time.

While this is simply a run-of-the-mill backup catcher signing, it is fascinating to see what skillset the Mariners are valuing in 2026 for their role players. With some of their struggles getting batters on base last season or leaving runners on, it is encouraging to see them being proactive in addressing these issues. Even in small deals such as this, the vision is clear. Having seen the Blue Jays’ approach come so close, it looks like they are taking a page out of the ‘contact-first’ book. Especially when they have the power at the top of the line-up to really make it count.