Arbitration eligible players who were non-tendered (not offered contracts) are now free agents. There were around 50 some players that will join the group of free agents already available this season.
The Mariners had just Ryan Rowland-Smith. Other teams had a few players, while others like the Twins had none.
But here's a list below that they put together of players that join current free agents
Angels: IF Kevin Frandsen
Athletics: DH/1B/ OF Jack Cust, OF Travis Buck, 3B Edwin Encarnacion
Blue Jays: OF Fred Lewis, RHP Jeremy Accardo
Mariners: LHP Ryan Rowland-Smith
Orioles: RHP Matt Albers
Rangers: RHP Dustin Nippert
Rays: RHP Lance Cormier, IF Willy Aybar, C Dioner Navarro, LHP J.P. Howell
Red Sox: LHP Hideki Okajima, LHP Andrew Miller, RHP Taylor Buchholz
Royals: 3B/OF Josh Fields
Tigers: RHP Zach Miner
White Sox: RHP Bobby Jenks, LHP Erick Threets
Yankees: RHP Alfredo Aceves, RHP Dustin Moseley
Astros: RHP Sammy Gervacio
Braves: OF Matt Diaz
Brewers: RHP Todd Coffey, IF Joe Inglett
Diamondbacks: RHP Blaine Boyer, OF Ryan Church, IF Augie Ojeda, RHP D.J. Carrasco
Dodgers: C Russell Martin, LHP George Sherrill, OF Trent Oeltjen
Giants: RHP Chris Ray, OF Eugenio Velez
Marlins: RHP Jose Veras, IF Ronny Paulino
Mets: RHP Sean Green, OF Chris Carter, RHP John Maine
Nationals: RHP Joel Peralta, C Wil Nieves, RHP Chien-Ming Wang
Padres: OF Tony Gwynn, OF Scott Hairston, RHP Matt Antonelli, RHP Luis Perdomo
Pirates: OF Lastings Milledge, SS Argenis Diaz, LHP Donnie Veal, LHP Brian Burres
Rockies: RHP Manny Delcarmen
Do any of them catch your eye? The Mariners still need depth in the starting rotation. They also could use help at catcher, left field, another infielder ... and anybody that can possibly provide some offense. But these players were non-tendered for a reason - they have diminished value to their respective team, particularly given their price tag.
For example Russell Martin is coming back from a serious hip injury, while Buck has no place in the plans of the A's in the future. Encarnacion is a butcher at third, but he has some power - maybe not Safeco Field power. There's Jack Cust, who has a near .400 OBP, but no position other than DH.
Could one of the players in the lists above help the Mariners? Certainly, but its a matter of finding the right fit and role, and most importantly, the right price. Just because these players have suddenly become free agents you shouldn't view them as significantly more valuable that the players that were already out there.
GM Jack Zduriencik will simply add these players to the myriad of others he's looking at to help the Mariners.