This story was excerpted from Daniel Kramer's Mariners Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

Contending teams can never have enough relief reinforcements, and despite boasting one of MLB’s best bullpens last year, the Mariners are no exception, particularly after trading high-leverage righty Erik Swanson in the Teoscar Hernández deal.

But Seattle might have an arm that could fill that void after agreeing to terms last week with Casey Sadler on a Minor League deal with an invite to Spring Training. Sadler, who missed all of last season recovering from right shoulder surgery, elected free agency after clearing waivers last month. 

It’s not a flashy free-agent signing, but it’s nonetheless an avenue in which the Mariners have addressed a need. Given their advanced pitching development program and numerous success stories with under-the-radar names -- such as Sadler in 2021 -- it’s also not the biggest priority. But it gives them more roster clarity and another arm competing for a spot in camp. 

“It’s nice to be relevant again,” Sadler joked in a phone interview this week. 

Given all the highs in Seattle in 2022 -- Andrés Muñoz, Matt Brash and Penn Murfee all emerging as legit leverage arms -- it’s easy to forget what Sadler contributed in ‘21, when he compiled a 0.67 ERA and a 620 ERA+ (league average is 100) while holding 145 opposing hitters to a .143/.207/.196 slash line in 40 1/3 innings.

Sadler is also riding a Mariners record, having finished 2021 going scoreless in each of his final 29 outings, a span of more than two months. Only three MLB pitchers matched that mark in 2022, the Brewers’ Devin Williams and the Yankees’ Clay Holmes, both All-Stars, and the Astros’ Ryne Stanek, who won the World Series.

Yet that season for Sadler, statistically, was an outlier, after hopping from Pittsburgh to Tampa Bay to the Dodgers and Cubs dating back to being a 25th-round Draft pick in 2010. He landed in Seattle after being claimed off waivers during the pandemic-shortened 2020 season, and after working with pitching coach Pete Woodworth, bullpen coach Trent Blank and the rest of Seattle’s gurus, Sadler -- like many of his ilk -- unlocked far more potential. 

“They really kind of explained maybe what you are or aren't seeing and feeling and what’s going on,” Sadler said. “And then translating that into, ‘Hey, this is kind of where you profile and this is what works. This is where your stuff kind of combats the hitter,’ -- all of that analytical stuff that they dive so far into.

“... Even on down to talking with the guys. We watch each other. We know when guys are right, and we know when something's not right. We kind of hold each other accountable, and you don't want to be the weak link.”

Remarkably, during quarantine that year, Sadler moved his family to the Snoqualmie Valley area, about 30 miles east of Seattle, creating the perfect geographical and team fit after he was designated for assignment by the Cubs. He’s one of just three Mariners who live in the area year-round, along with J.P. Crawford and Marco Gonzales. Having his wife and two daughters nearby once the season gets going is why Sadler yearned to return.

“I think sometimes our families kind of get lost in the shuffle just with how crazy the summers are,” Sadler said. “I've seen that kind of take a toll on my daughters a couple of times, and it's just being able to give them that sense of, ‘Hey, we could just stay home.’”

That, and he really grasped onto the Mariners’ fan base by engaging with them regularly via social media, even while sidelined.

“Mariners fans are the best,” Sadler said. “I think I really missed that kind of rush when you run out on the mound or come off the mound. I’m so looking forward to that again.”

Sadler filled the perfect bridge role for manager Scott Servais the last time he was regularly on the mound as the first bullpen arm after the starter. He’ll be up against whoever else the club invites on similar Minors deals, but he’s on track with his throwing program to be 100% in camp, and if there are hiccups, it’s possible he begins the year at Triple-A Tacoma. Regardless, he’s looking forward to the opportunity.