The Seattle Mariners were able to do in December something they haven’t done in the fall for years: be relevant both in their own football-crazy town and to baseball observers around the country.

Funny how spending $240 million on one of the game’s best players will do that for a struggling franchise.

But now that baseball season is here, the question is whether or not the Mariners can turn an offseason splash into success the team hasn’t known in more than a decade. Having two legitimate stars in the form of Robinson Cano and Felix Hernandez is great and all, but if that doesn’t translate to more success, the Mariners will again be in danger of being tuned out as soon as their Super Bowl champion neighbors open training camp in late July.

So how can the Mariners stay in playoff contention into August, and perhaps beyond? And let’s face it, when you’ve been losing as long as the Mariners have, and when you have so much money invested in two stars in their prime, that’s the minimum standard for success in 2014. Well here are five ways the Mariners can be a team that holds our interest into autumn:

1. Have Felix be Felix, and Robinson be Robinson

In all reality, for the Mariners to succeed, the key is going to be what everyone beyond their top two players is able to do. That being said, if either Cano or Hernandez has an uncharacteristically bad season, or is limited by injuries, there is almost no chance that the Mariners have enough offensive firepower or pitching depth to survive.

The good news in this regard is that both of Seattle’s stars have been both consistent and durable in their careers, which is precisely why they’re two of the highest-paid players in the game, and two people who should be the least of your concern in 2014. As for everyone else, however…

2. Get serious production beyond Cano

The Mariners were hoping to add a proven right-handed bat to bolster their lineup, but didn’t find the right fit. Instead, they’ll have to hope that Corey Hart, who missed all of last season and is coming off surgery on both knees, can somehow return to his all-star form and be that right-handed bat. Or perhaps catcher Mike Zunino can take a step forward and add some right-handed pop after being rushed to the majors last year.

Or maybe the Mariners just live with an unbalanced lineup, which isn’t ideal but would be fine if Brad Miller can build off of a torrid spring, or if Kyle Seager can continue to be one of baseball’s best young third basemen, or if Logan Morrison, another once-promising, since-injured player can regain the form he showed three years in Miami, or if the promising yet inconsistent Michael Saunders can finally put together a solid seasons, or if Justin Smoak…

OK, you get the point. There’s a lot of hope and ifs in the above two paragraphs. Hey, nobody said turning things around was going to be easy.

And the Mariners offense doesn’t need to just be better, it needs to be good enough to help overcome pitching question marks and defensive liabilities. That’s asking a lot from a lineup with one proven star, a very good third baseman and a whole lot of players who are either trying to live up to yet unreached potential or come back from significant injuries.

3. Survive the early pitching injuries

When healthy, the Mariners rotation is perhaps a little less experienced than is ideal, yet still loaded with enough talent to make you think they could have something special. When the season opens Monday, however, Seattle’s rotation will be far from healthy, with All-Star Hisashi Iwakuma and top prospect Taijuan Walker both in the disabled list.

The good news is that both are expected back soon, but the bad news is that they’re being replaced in the rotation by Roenis Elias, a talented prospect who despite all of his upside has never pitched beyond Double A—anybody remember Brandon Mauer attempting the same leap last year?—and the recently-signed Chris Young, a veteran righty who is yet another let’s-hope-he-can-recapture-his-pre-injury-form guy.

If Felix can be Felix, and if James Paxton can overcome his own inexperience, and if Erasmo Ramirez can pitch like a solid No. 3 starter, the Mariners should be able to tread water until Iwakuma and Walker return. If not, the Mariners could find themselves trying to dig out of an early hole.

4. Overcome defensive shortcomings (or just be better defensively than we all think they are)

The Mariners are actually in pretty good shape when it comes to infield defense—though they’ll take a step back at first base on the days Justin Smoak is off—but when it comes to Seattle’s outfield, there are plenty of concerns depending on that day’s particular lineup. Gone are defensive liabilities Raul Ibanez and Michael Morse, but while Dustin Ackley is a much better athlete, he’s still a natural infielder adjusting to the outfield move he made last year. Michael Saunders is more than capable in the outfield, but will have to hit well enough to justify his place in the lineup every day, and the same can be said of Abraham Almonte. Where the potential issues could come up is if Hart and Morrison are hitting and manager Lloyd McClendon feels like he has to get both in the lineup, which would on most days mean using one as a DH and the other in the outfield.

Just about any outfield combination the Mariners use this year will probably be a defensive upgrade over last year, but defense still could be an issue, particularly early on when the rotation is at less than full strength.

5. Have Lloyd McClendon finally be the right manager

If you’ve heard Lloyd McClendon talk baseball since he was hired by the Mariners in November, you’ve likely come way impressed with the new manager. Problem is, the same could be said about Eric Wedge, Don Wakamatsu, Mike Hargrove and the rest of the managerial revolving door in Seattle since Lou Piniella left.

McClendon, who is in his second go-around as a manager after a long stint on Jim Leyland’s staff in Detroit, can’t by himself be the difference maker this year, but he can help set the tone for a team trying to move past a decade of struggles.

“If you’re going to win, there are certain things that you have to do and there’s a certain way that you have to prepare,” McClendon said before the start of spring training. “And part of that belief is that when you step between the lines, you have to believe, ‘On this given day, I’m the best person out there.’”

McClendon has talked about changing the culture in Seattle, and he made a statement early that will go over well with his team when he stood up for Cano after Yankees hitting coach Kevin Long questioned the second baseman’s hustle. The Gary, Ind., native seems like the perfect, no-nonsense man to lead a turnaround, but turning an impressive first impression into a winning season has proven challenging for past Mariners managers.

Herald Writer John Boyle: jboyle@heraldnet.com.