The A’s and Giants don’t have much in common these days. One team won 97 games with a tiny payroll, and the other won 73 with a huge payroll.

But both need to solidify their rotations and certainly will discuss starting pitchers at the upcoming general manager meetings in Carlsbad, just north of San Diego.

With Madison Bumgarner a year from free agency, Johnny Cueto coming off Tommy John surgery and Jeff Samardzija a mystery after winning one game and posting a 6.25 ERA in 10 starts, suddenly the Giants’ so-called big three is more of an unknown than Dereck Rodriguez and Andrew Suarez; that is, unless one of those promising rookies is dealt for a hitter.

The A’s had no shortage of starters, but most either declared for free agency or are expected to open next season on the disabled list, leaving few certainties for 2019.

GMs will gather Monday and engage in meetings Tuesday, Wednesday and part of Thursday. While the A’s are sending their top decision-makers, the Giants — who still haven’t hired a baseball operations chief, meaning it’s anyone’s guess which direction they’ll go — are sending assistant GM Jeremy Shelley to be their front man.

With Clayton Kershaw taking himself off the market by re-upping with the Dodgers, the top free-agent starters are Patrick Corbin and Dallas Keuchel. The next tier includes Hyun-Jin Ryu, J.A. Happ, Nathan Eovaldi and Charlie Morton, who, like CC Sabathia has hinted he’ll retire after one more season.

Other names: Gio Gonzalez, Anibal Sanchez, Matt Harvey, Lance Lynn, Wade Miley and Derek Holland, who could re-sign with the Giants.

While the A’s are deep enough in other areas to focus mostly on the rotation, the Giants have several pressing needs, not the least of which is rebuilding the outfield with power bats and solving their late-inning relief.

•How will the Kershaw signing (three years, $93 million) affect Bumgarner? Kershaw is 30, the same age Bumgarner will be when he becomes a free agent a year from now. It would be an insult for the Giants to ask Bumgarner to take a hometown discount because that’s exactly what he has taken for several years. In fact, even though the pitchers are a year and a half apart in age, Bumgarner’s career income ($46 million) has been less than one-third of Kershaw’s ($165 million). Bumgarner will make $12 million next year and then is due for a significant bump. It’s one of the first major decisions the Giants’ new boss needs to make: Keep the World Series hero for 2019 or trade him for a legitimate hitter (preferably an outfielder) or a high-end prospect or two. Another option is to do what the Dodgers did with Kershaw and tear up Bumgarner’s remaining contract and agree on a long-term deal, which many Giants fans would welcome.

•A’s second baseman Jed Lowrie turns 35 in April, an age when a player’s value quickly diminishes if it already hadn’t done so, but Lowrie is coming off a career year, which leaves the A’s in a predicament. No doubt Lowrie wants a multiyear deal, but why would the A’s budge beyond one year if they truly believe in Franklin Barreto, the heir apparent? For now, the A’s are saying they want Lowrie back, but whether their dollars and years measure up to their words is a story that’ll play out. If the A’s agree to an extended deal for Lowrie, it would show they aren’t totally sold on Barreto. On the other hand, if the A’s are slow to move on Lowrie, he might find an offer to his liking elsewhere.

•Catcher Jonathan Lucroy is Oakland’s other free agent from the everyday lineup, but unlike in Lowrie’s case, the A’s have no one in the system ready to assume starting duties. Josh Phegley is a backup, Bruce Maxwell’s stock nosedived and Sean Murphy needs seasoning in Triple-A. An argument could be made that it’s more important to bring back Lucroy than Lowrie. Lucroy’s numbers dropped, but he was a vital presence because of his defense and leadership and how he worked with Oakland’s boatload of pitchers. It just so happens the free-agent market is full of catchers who won’t break the bank on one-year deals. The biggest multiyear deal should go to Yasmani Grandal, who looked far more equipped in the regular season than postseason. The rest of the list includes Martin Maldonado, Wilson Ramos, old friend Kurt Suzuki, Robinson Chirinos, Matt Wieters, Brian McCann and Nick Hundley, some of whom have hit better than Lucroy but don’t match up defensively.

•The Mets gave new GM Brodie Van Wagenen the authority to decide if manager Mickey Callaway will return — yes, Callaway is coming back — while the Giants took a different approach, announcing Bruce Bochy will return before deciding who’ll oversee the front office. Granted, Callaway has one year of experience while Bochy is going to the Hall of Fame, but it shows the difference in organizational mind-sets. The Giants’ hire will have no choice but to inherit Bochy, not as if he/she wouldn’t want him anyway to orchestrate a season of transition. Bochy has never had a problem moving from one boss to another, and the next one will be his fifth.

•The Giants won’t pay a luxury tax for the first time in four years after staying beneath the competitive balance tax threshold of $197 million. That gives them freedom to exceed next year’s threshold of $206 million without paying a 50 percent tax. It would be just 20 percent. That provides more flexibility to enter the Bryce Harper sweepstakes, if indeed that will remain the intention. Other free-agent outfielders include A.J. Pollock, Michael Brantley, Nick Markakis, Carlos Gonzalez and versatile Marwin Gonzalez. Oh, and Andrew McCutchen.

John Shea is The San Francisco Chronicle’s national baseball writer. Email: jshea@sfchronicle.com Twitter: @JohnSheaHey