Former Reds ace might hold the key to Josh Naylor's next landing spot

Josh Naylor remains one of the more intriguing free-agent fits for the Cincinnati Reds. While splitting time between the Arizona Diamondbacks and Seattle Mariners in 2025, Naylor hit .295/.353/.462 with a 128 wRC+. He also hit at least 20 home runs for the third time in the past four seasons, and brought his strikeout rate all the way down to 13.7% this year. He's also a proven postseason performer.

That's the kind of player the Reds should want on their team as they prepare for their first serious window of contention in 12 years, but in truth, they may not control their own fate in this pursuit.

Curiously, Cincinnati's chances of signing Naylor may come down to what the Seattle Mariners do with former Reds' ace Luis Castillo this winter.

Luis Castillo's fate could determine whether Reds can sign Josh Naylor in free agency

Following their run to the American League Championship Series last month, the Mariners have made it clear they want to keep the band together, including Naylor. However, after his brilliant season, they made struggle to do so. Recent contract projections peg Naylor as a likely candidate to receive somewhere in the vicinity of $20 million per year, which would mean a nine-figure contract over a five-year period.

The Mariners can certainly afford that number, but their $165 million payroll in 2025 was already the largest in franchise history. Giving Naylor a contract worth $20 million per year would push their estimated 2026 payroll near that amount, and that's before the team makes any outside additions to reinforce the roster.

Thus, Castillo, who is the team's highest paid player ($24.15 million salary in 2026 and 2027), may need to be moved in order for the pitching-rich Mariners to keep Naylor in tow. Castillo remains one of the more consistent frontline starters in the sport — 3.54 ERA in 180 2/3 innings this season — so the question may be if the Mariners are willing to trade him in order to make room for Naylor.

Even with Spencer Steer and Sal Stewart, Naylor would make for a fine addition to the Reds' roster this winter. It's weird to root for a former Reds ace to stay put in his new home, but if Cincinnati is going to get a chance to court Naylor this offseason, Castillo may need to stay planted in the Pacific Northwest.