The Giants have the second-worst record in the Major Leagues, along with the National League's second-oldest group of position players, according to Baseball-Reference.com's weighted calculation. That's a discouraging combination.

Industry sources believe San Francisco general manager Bobby Evans has three true untouchables: ace Madison Bumgarner , catcher Buster Posey and shortstop Brandon Crawford . Most of the remaining players likely will be available, to varying degrees, between now and July 31, even if the odds of a Johnny Cueto or Mark Melancon deal aren't especially high.

Bumgarner is off the board for a variety of reasons: His value is at a (relative) low point after spraining his throwing shoulder in a dirt bike accident, although he's already begun a Minor League injury rehabilitation assignment; the Giants hold affordable options on him for the 2018 and '19 seasons; and Evans would rather not create another vacancy in a rotation that will lose Player Page for Matt Cain and possibly Cueto after this year.

Cueto plans to opt out of the remaining four years and $84 million left on his contract after this season, according to Jon Heyman of fanragsports.com. Presumably, an injury would prompt Cueto to reconsider. Thus, suitors must consider the massive downside risk and short-term benefit. And given Cueto's performance this year -- a 1.291 WHIP is his worst since 2009 -- other GMs aren't rushing to make a complicated deal.

Melancon is a more intriguing trade possibility, if only because his previous team -- the Nationals -- still lacks a permanent closer and clearly was prepared to pay big money for one last winter. There's been friction between Melancon and his bullpen mates regarding pregame routines this season, as detailed by Ken Rosenthal of FOXSports.com, which makes a trade more plausible.

Still, a relief pitching contract of Melancon's size -- three years, $53 million left after this season -- never has been moved at the non-waiver Trade Deadline.

Evans and his staff are certain to have very difficult conversations regarding which players truly are part of the team's core. If Giants officials convene and compile the names of every player who absolutely must be on next year's team, the list likely stops after Bumgarner, Posey and Crawford.

Brandon Belt , in particular, could be an intriguing fit for the Angels, who need a left-handed presence at first base and will benefit from payroll flexibility in 2018 with the expiration of Josh Hamilton's contract. Belt leads the Giants with 14 home runs.

• Speaking of left-handed-hitting first basemen: Lucas Duda of the Mets has an .896 OPS in June. Duda, like Oakland's Yonder Alonso , plays for a seller and will be a free agent after this season.

If the Giants show a willingness to engage in talks on Belt, teams like the Angels, Yankees and Mariners will have plenty of options to consider at the position over the next month.

• One reason why the Tigers will consider trading Justin Verlander : Even in a down year by his standards, he has perhaps the most extensive marketplace of any Detroit player signed to a big-dollar multiyear deal. And Tigers general manager Al Avila would love to move payroll.

The desire to save money is not exactly novel among Major League Baseball franchises, but the concept has particular resonance for the Tigers: Their payroll is roughly $205 million, according to spotrac.com; that is about $10 million over MLB's luxury tax threshold. After paying the tax following the 2016 season, the Tigers would be subject to an even higher rate if they exceed $195 million in payroll this year.

No team wants to pay a large tax bill after finishing with one of the worst records in the AL -- which is what the Tigers are on pace to do.

One more note on the luxury tax: If teams include cash in trades, that money still counts as part of the "selling" team's payroll calculation. In other words, if the Tigers pay all of Verlander's salary in order obtain better prospects, the transaction won't help to reduce their payroll for luxury-tax purposes.

Avila faces difficult choices in that regard, considering how badly the Tigers' farm system needs an infusion of talent at its upper levels.