It's been more than four years since Robinson Cano first put on a Seattle uniform, and more than two since Jerry Dipoto took over as general manager of the Mariners.Dipoto was supposed to bring a radically different school of thought to the Mariners' front office and lead the team to succe s. Cano, signed by predece sor Jack Zduriendcik, was supposed to spearhead a push for relevancy, backed by Felix Hernandez, Nelson Cruz and Kyle Seager.Two years isn't a lot of time to turn a stumbling franchise, but Dipoto has had plenty of pieces to play with. He's made trade after trade, waiver claim after waiver claim. The 40-man roster has undergone a near-constant overhaul. Only seven players who held a 40-man spot in 2015 are still among the group (Cano, Hernandez, Cruz, Seager, James Paxton, Mike Zunino, Tony Zych).All the roster shuffling hasn't amounted to much, and there have been mi steps along the way. Dipoto freely admits to bungling the Chris Taylor trade, for instance. The Mariners still haven't made the playoffs and have what may be the worst farm system in baseball. Given Seattle's aging roster, this season may be the last gasp of life for the Mariners'contention window and it's probably not going to go very well.FOSTER: 18 things I really want to see in the 2018 seasonSeattle won 86 games in Dipoto's first full season, and then fell to 78 wins. The 2017 Mariners dealt with injuries galore, but were ill-equipped to deal with even just some of them. Ariel Miranda logged a 5.12 ERA and led the team in innings.Again, two years isn't a lot https://www.tigersedges.com/detroit-tigers/jordan-zimmermann-jersey of time to a semble a playoff team out of the wreckage of one of the game's most notoriously dysfunctional franchises. There were positives in the 2017 season, including the acquisition of Jean Segura, even if it meant watching Taijuan Walker blo som in Arizona. James Paxton broke out in his limited time. Zunino started to hit. Ben Gamel and James Pazos looked like solid contributors.How much of that will carry over into this season remains to be seen, as well as whetherthe newly acquired Dee Gordon can play center field, and whether Ryon Healy can give enough help with his bat.Yet the Seattle rotation doesn't seem to be anywhere near up to snuff. Hernandez, as great as he once was, is now entering his Age 32 season and hasn't pitched like an ace since 2015. He mi sed most of last year with shoulder i sues. Paxton, as great as he was, mi sed time with two different muscle strains. The highlight of the rest of the group is Mike Leake, which should say enough.The depth behind these starters is largely the same group of uninspiring facele s starters who threw far too many innings in 2017. Health has been an i sue for the Seattle rotation for years now, of course, yet Dipoto hasn't exactly put meaningful depth behind his rotation. The Mariners can'tafford another 59 innings of Andrew Moore, to say nothing of letting Miranda repeat his 2017 workload.The farm is littered with uninspiring options such as Max Povse and Rob Whalen, who were acquired in a trade that sent former top prospect Alex Jackson to Atlanta. Povse and Whalen look like little more than filler, while Jackson has had something of a resurgence with the Braves. Seattle's top pitching prospect was sent to Miami in the Gordon trade.FAGAN: Ranking the five best bullpens in baseballTo be fair to Dipoto, the Mariners made a strong campaign to sign Shoehi Ohtani, who would have made an enormous impact on their rotation. Yet Dipoto now says that he doesn't anticipate that he'll sign another starting pitcher. There are still four good starters out on the market. Obviously someone like Yu Darvish would be an enormous boost Omar Infante Jersey , but even Lance Lynn could provide plenty of quality innings.Instead, the Mariners will go forward with what they have. The starters will be backed by a bullpen that now features Juan Nicasio and a full season of David Phelps, which should help. The formula had better work. Because of the tumbleweeds on the farm, it will be extremely difficult for Dipoto to make a meaningful upgrade should the Mariners find themselves in relative contention near the trade deadline. Even reaching that point may be a tall order, given the overwhelming strength of the Astros and the fancy new toys of the Angels.If the Marinersdon't contend this season,Seattle may be looking at a long rebuild. Cano is coming off his worst offensive season by OPS+ since 2008. Hernandez's performance is declining, and all the mileage on his body may be showing. Neither one is getting any younger. Nelson Cruz is in the final year of his contract. The only meaningful help on the way may be in the form of Kyle Lewis, who has lost time to a bad knee injuryand has yet to play above A-ball. If the Mariners are in the middle of the pack come July, they'll be at a cro sroads.MORE: White Sox tout family culture as rebuild chugs alongDipoto has gone for it, albeit in his ownway. He has https://www.tigersedges.com/detroit-tigers/miguel-cabrera-jersey tried to make his team a winner. Regre sion and the injury bug came for the Mariners in 2017, as they always seem to do, and it may have been the penultimate nail in the coffin. Even if Dipoto did lure Darvish to the northwest, it would be difficult to see the team as better than the ones in Houston and Anaheim. But the team is on its last breaths, and signing a good starter could mean getting good prospects in a trade if things go south.History teaches us that the Mariners will try, and that, somehow, misfortune will befall them. There's no underlying metric telling us that the Mariners are trapped in a Metsian version of "Groundhog Day," that they'll keep tripping over their own shoelaces until the eventual heat death of the universe. At some point, they will break through.It just looks unlikely that it will be this year, or any year in the near future. This may be the final chapter of this version of the Mariners. Dipoto may want to do his best to make this chapter as strong as he can. The sequel is probably a long wayoff.