Mariners fans everywhere are tremendously excited over the way that the offseason leading into 2010 has gone, and rightly so. Chone Figgins, Cliff Lee, Milton Bradley, and Brandon League are excellent reasons to raise your hopes for the upcoming season, as is how cheaply the Mariners acquired those players. However, there still are a few spots to fill, and there are uncertainties as to who might fill those holes.

With the acquisition of Casey Kotchman filling the hole at first base, the attention of many fans has turned to the bench. The departure of Bill Hall in the trade for Kotchman left a void there for a player who can play in both the infield and outfield as well as a spot for a right-handed bat. Popular opinion has tended towards Fernando Tatis and Jerry Hairston, Jr. for this role on the team, and both are good options. Tatis can play left field at a fringe-average level, and can play anywhere in the infield without being an embarrassment. Hairston is a defensive whizkid, who can play all over the infield and outfield, and plays at at least an average level at each position. Neither player has a particularly fearsome bat, but they won’t kill you at the plate either (both project to a slightly below average wOBA in 2010). The drawback for both players, however, is that both are firmly in the decline phase of their careers (Tatis is entering his age 35 season, Hairston his age 34 season), and either one will probably cost between $2 million and $3 million for the 2010 season.

There is, however, one player that Mariners’ fans seem to have overlooked in the midst of the player acquisition frenzy the organization has undergone this offseason. Indeed, this player is already a Mariner.

Matt Tuiasasopo.

Penciled in to be the team’s starting third baseman before Figgins was signed, Tuiasasopo has largely become a forgotten man during the course of the offseason. He’s actually a beautiful fit for the role the Mariners have open. Tuiasasopo has played both third base and second base at the major league level, was drafted into the organization as a shortstop, and has been experimented with as a corner outfielder (although not yet in a game situation). Heck, if Jose Vidro can play first base without looking like an idiot, so can Tuiasasopo. His bat is still developing (he’s entering his age 24 season), but shows promise and would likely profile similarly to Tatis’ bat in 2010.

Plus, the average fan will love him because he’s a local product and a member of the Tuiasasopo family that’s had such a huge impact on University of Washington football (in fact, Matt had committed to play football for UW before being drafted by the Mariners). That he’s a minimum salary player already on the 40-man roster is just gravy for the organization.

There is an argument that Tuiasasopo should stay in Tacoma until he’s more prepared for a starting role, but he just won’t get that kind of opportunity with the Mariners. Figgins is blocking him at third for the next few years, Lopez and Dustin Ackley block him at second, and a host of quality prospects block him out of left field. Unless the team intends to trade him, a utility role like this is the best use of Tuiasasopo’s talents, and it’s a role that he should be able to provide good value to the team.

Does this mean Tuiasasopo will be that super utility guy, and likely the 25th man on the roster? Not necessarily, but the fit is there should the Mariners choose to look internally to fill that role, and it’s a fit that makes a fair amount of sense once you take the time to remember that he is an option.