#2: Marco Gonzales
Like with Flexen, I feel for Marco. At the start of 2021, he was the "Ace" of the Mariners rotation. It's not that he was actually an Ace, but he was the top pitcher on the team, the leader, and one of the vets for the squad. He was coming off of a dominant 2020 in which he posted career bests in ERA, FIP, innings per start, WHIP, BB/9, K/9, and actually led the league in both BB/9 and SO/W.
Since, his ERA has been decent still at 4.05, but it's the surrounding numbers that are more concerning. A 1.259 WHIP is good, but the 5.15 FIP shows that he has essentially been lucky. His BB/9 is up to 2.55 and he's given up 59 HR in 326.1 IP across 57 starts. Marco is less likely to be traded than Flexen, but with a handful of prospects close to the majors, the Mariners are going to have 4-5 guys fighting for one rotation spot, and Marco could be the odd man out.
It should be noted that his contract will make him a bit more unlikely to be traded as well. He makes $6.75M in 2023 and $12.25M in 2024. He then has a club option in 2025 for $15 million.