Bay, 34, was released by the Mets last year with $19 million still remaining on his contract after three tough seasons in New York, but has been relaxed and productive with the Mariners from the start of camp and said he's eager to do whatever he can to help this season.
"The fresh start is the big thing," he said. "No matter what I was going to do in New York, it wasn't going to be enough to make up for all the things I didn't do. And I understood that. That's why we came to the realization that a clean break was probably best for everybody and I came here knowing and being comfortable I wasn't competing for a starting job.
"I knew that and embraced it," he said. "I consider myself a realist. I look around and see what's going on and know where I stand and what my job is going to be. And I'm excited about it."
Manager Eric Wedge said the veteran Bay was "a better fit" for what the Mariners were looking for going into the season.
"Jason had a good camp for us," said Wedge. "He's a solid veteran player. He's a guy who came in in great shape. Moved around great all spring. Short, quick swing. I liked the way he moved around the bases. I liked the way he moved in the outfield and I like what he brings to the clubhouse. Just a lot of positives there."
Four other players were sent down to the Minor Leagues on Sunday: right-handed reliever Danny Farquhar, catcher Jesus Sucre, infielder Brad Miller and veteran outfielder Endy Chavez.
Those moves bring the Mariners roster to the required 25-man limit. Here's the club that will open the season Monday at 7:07 p.m. PT in the Oakland Coliseum:
Starting pitchers: Felix Hernandez, Hisashi Iwakuma, Joe Saunders, Brandon Maurer and Blake Beavan.
Relievers: Tom Wilhelmsen, Stephen Pryor, Carter Capps, Kameron Loe, Charlie Furbush, Oliver Perez and Lucas Luetge.
Catchers: Jesus Montero and Kelly Shoppach.
Infielders: Justin Smoak, Kendrys Morales, Dustin Ackley, Brendan Ryan, Kyle Seager and Robert Andino.
Outfielders: Michael Saunders, Franklin Gutierrez, Michael Morse, Raul Ibanez and Bay.
By making the 25-man roster, Bay is now guaranteed all $1 million of the Major League contract he signed with the Mariners in December. That deal assured him only $500,000 unless he made the team.
He'll also be eligible for up to $2 million more in bonuses if he accumulates enough playing time this season. The deal kicks in an extra $250,000 if he reaches 350 plate appearances, with another $250,000 every additional 25 plate appearances up to 425 and then $200,000 at additional levels from 450 up to 550.
But Bay said he's not worried about playing time.
"I knew coming in I wasn't going to play 162 games here," he said. "I'm really looking forward to just contributing any way I can. It's a different part of my career. I understand that. That being said, injuries and things happen. But I'm very comfortable with it. I talked to Wedge and [general manager] Jack [Zduriencik] about where I stand and I think everybody sees it.
"You're the fifth outfield guy and what happens happens. But I'm actually quite happy with that. It's a fun clubhouse; there's a lot of reasons to be excited. And rather than look at it as what you're not doing, I look at is as what I am doing. When I get in there, it'll be fun and it'll be baseball."
The veteran slugger played well all spring after signing with Seattle, hitting .321 with two home runs, six RBIs and a .938 OPS (on-base plus slugging percentage) in 53 at-bats.
Wells is an excellent defender who hit .225 with 17 home runs and 51 RBIs in 124 games for the Mariners over the past two seasons. He batted .189 with two homers, 14 RBIs and a .646 OPS in 53 at-bats this spring.
The club also added right-handed pitcher D.J. Mitchell to the 40-man roster, then optioned him to Triple-A Tacoma. Since Wells is out of Minor League options, that move allowed Wells to be designated for assignment rather than released, which gives the team 10 days now to either trade him, release him or outright him to the Minors.