Top 50 Seattle Mariners

The Seattle Mariners began as an expansion team in 1977, and like many expansion teams, they took their lumps in the beginning.  It took them until 1995, where they would not make their first playoff until 1995 with a team comprising of Alex Rodriguez, Ken Griffey Jr. Randy Johnson and Edgar Martinez, the sky seemed to be the limit, and they would make the playoffs in 1997, 2000, and 2001, but they were unable to win the American League Pennant.

To date, the Mariners are the only Major League Baseball team that has not participated in a World Series.

This list is up to the end of the 2020 season.

Note: Baseball lists are based on an amalgamation of tenure, traditional statistics, advanced statistics, playoff statistics, and post-season accolades.

As of this writing, Mitch Haniger is set to enter his fifth season with Seattle, and the hope is that he can regain the magic that he had in 2018. 
After playing a decade in Japan with Yokohama, Kazuhiro Sasaki was a 32-year old rookie in Seattle, and with a decade of real experience, he easily won the 2000 American League Rookie of the Year Award.  The former Central League MVP would finish third in the AL with 37 Saves.
While J.J. Putz and Kaz Sasaki are ranked higher and (we feel) had a better overall Career in Seattle, the most excellent season that a reliever had in a Mariners' uniform should be attributed to Edwin Diaz.
Tom Paciorek made his debut in the Majors in 1970 with the Los Angeles Dodgers, and he saw little action with L.A. when he played there until 1975.  The Atlanta Braves had him next but released him in May of 1978, and by that time, he was 30 and had never been more than a platoon player.  The Mariners would sign him days later, and the First Baseman remained as a platoon player, but he would see more action in 1980 and would have 114 Hits.  That was good, but in 1981, he had an unexpected season.
A year after he was an All-Star in 2002 with the Tampa Bay Devil Rays, Randy Winn was traded to the Seattle Mariners. 
Carlos Guillen's career took off with the Detroit Tigers, but his Major League career began in Seattle.
After being drafted in the 12th Round of the 1997 Draft, Joel Pineiro would reach the majors in 2000, and made it to the Mariners starting rotation in 2002. 
Historically speaking, Ruppert Jones was very important in the early days of the Seattle Mariners.  He was the first player chosen in the Expansion Draft, after playing a handful of games with the Kansas City Royals, and in the inaugural season of the Mariners, Jones went to the All-Star Game.  He would have a career-high 24 Home Runs that season with a .263 Batting Average.
The fact that Leon Roberts had a Major League career at all was impressive, considering that he withheld poor vision from his teammates and management.  Regardless, he fought for a spot in Baseball, and his best years happened in Seattle.
Marco Gonzales was a First Round Pick in 2013 by the St. Louis Cardinals, but the Seattle Mariners were able to obtain him in a trade for Tyler O’Neill in the summer of 2017. Gonzales had made it to the Majors by that point, but he had not yet proven himself as a bona fide Starting Pitcher at baseball’s highest level.  This would change in the Emerald City.
Matt Young had a losing record as a rookie (11-15), but that was in 1983 when he was not going to receive a lot of offensive support.  His ERA of 3.27 and 130 Strikeouts were decent, and he was named to the All-Star Game as a rookie.  This might have been the best year of his career, as the Southpaw's ERA was much higher in the two years that followed.  He would lead the AL in Losses in 1985 and was demoted to the bullpen the year after.  
A former Olympian with Team U.S.A. in 1984, Scott Bankhead was a rookie with the Kansas City Royals in 1986 and was traded to the Mariners in that off-season.