While the top two free agents of this upcoming class duke it out in the World Series, the rest of the baseball world prepares for an offseason certain to be filled with many twists and turns as 28 clubs try to put themselves in position to be where the Astros and Nationals are.

We all know Gerrit Cole and Anthony Rendon are going to get paid this winter, but there are several talented free agents whose value is a little tougher to define. Some teams may view them as rock-solid options, while others might have questions about them.

Here are six players whose free agency fits that mold, complete with analysis from a number of Major League executives. (Players are listed alphabetically.)

Nicholas Castellanos, RF

Nobody buoyed their free-agent value during the final two months the way Castellanos did, posting a 1.002 OPS with 16 home runs in 51 games after being acquired by the Cubs. If that’s the type of hitter teams can expect, he should cash in with a healthy deal this winter.

Castellanos' July trade to the Cubs also means he is ineligible to receive a qualifying offer, which should help him draw the interest of suitors who would be otherwise unwilling to sacrifice Draft picks to sign a free agent.

“Not having a qualifying offer helps, as does his age,” an American League exec said of Castellanos, who turns 28 in March. “He finished real strong.”

As impressive as Castellanos was during his two-month stint with the Cubs, the first four months of his season with the Tigers were nothing short of disastrous. He posted a .790 OPS with 11 home runs in 100 games, and lest we forget, his defensive reputation is less than stellar.

Castellanos’ defense actually improved slightly in 2019, and the fact that the Cubs were willing to run him out there on a nightly basis down the stretch could help change the perception that he’s a defensive liability.

“For Theo [Epstein] and that front office to use this guy during a playoff run and have it be OK might make some GMs feel comfortable taking a shot on him,” an National League executive said. “They could think, ‘Hey, the Cubs did it.’”

Still, it’s far more likely that he winds up with an AL team, reducing the number of interested clubs -- “This could be one with a high risk of the player having to wait deep into the winter,” an AL executive said. “Think of J.D. Martinez as a good comp for how his free agency could go [in terms of the long wait].”

Optimistic view: “I think he helped himself a lot in the second half,” an NL executive said. “He can really hit; if I was an AL club with a DH spot, I would have pretty heavy interest. I don’t know that he is J.D. Martinez, but you can draw some parallels to their stories. And he’s ahead of where Martinez was at his age.”

Pessimistic view: “The challenge for him will be teams that slant toward defense,” an NL talent evaluator said. “He’s viewed more as a DH long term than as a capable defender, which could limit his market.”

Josh Donaldson, 3B

It’s difficult to think of a player who had a better season after signing a “pillow” contract than Donaldson, who made the most of his one-year, $23 million deal with the Braves.

The former AL MVP posted a .900 OPS and hit 37 home runs while playing in 155 games, putting his injury-riddled 2018 campaign behind him.

The biggest knock on Donaldson is his age, as he’ll turn 34 in December. As previously mentioned, he played in 155 games, starting 148 at third base without the benefit of the DH in the NL.

There will also be the matter of a qualifying offer, which the Braves are virtually guaranteed to extend to Donaldson.

“The qualifying offer makes it tricky,” an AL executive said. “There will be a market for him, but that QO might impact him because of his age. Most teams will look for a two-year deal, though an AL team could go three with the DH in play. It only takes one team.”

Optimistic view: “The difference between him and the rest of these guys is that he has potential MVP-type impact,” an NL executive said. “If it’s the finishing piece, maybe you’re OK with it because the upside can mean a World Series title. For a contending club where he becomes what he was for Atlanta this year -- that last big piece -- maybe somebody gives him an extra year just to get him.”

Pessimistic view: “The most challenging part with Josh is that he’s turning 34, but he’s coming off one of his four best offensive seasons,” an NL talent evaluator said. “Is that a trend or is that a bookend to a really good career?”

Yasmani Grandal, C

Grandal is one of the biggest offensive threats among catchers; his .848 OPS in 2019 ranked second among all backstops with at least 400 plate appearances. For a position that often lacks much pop, Grandal certainly provides that and more.

Last year, Grandal rejected the Dodgers’ qualifying offer, which impacted him on the open market. He reportedly turned down a four-year, $60 million offer from the Mets, ultimately signing a one-year, $18.25 million deal with Milwaukee. Like Donaldson, Grandal bet on himself.

“His best- and worst-case scenario hinges more on him and his ego than anything that the marketplace will determine,” an NL talent evaluator said. “Not much changed this year than was the case last year. He’s the same player, only a year older. There comes a point in time when you have to cash in.”

Because he got the qualifying offer last year, Grandal is ineligible to receive one this year, which could open his market following another productive offensive year.

Grandal’s defensive skills are a bit deceptive. On the surface, he is below average, having led his league in passed balls in three separate years. However, he is an excellent pitch framer, as he ranked tied for second this year with +13 runs saved via framing, according to Baseball Savant’s catcher framing metric.

If NL teams are scared of the prospect of signing Grandal to catch into his mid-30s, his market could become more AL-centric thanks to the presence of the DH.

Optimistic view: “He’s had to do the one-year thing, so he should be eager to find a multiyear deal,” an AL executive said. “There are enough analytical teams that will look past his defensive flaws, and he’s one of the better offensive players at the position. He’s a good framer, which still matters.”

Pessimistic view: “You need him in the lineup, but he can cost you behind the plate,” the NL exec said. “You can argue his defensive value, but then again, he’s always in the playoffs. You just can’t be terrible and always go to the playoffs.”

Didi Gregorius, SS

Gregorius was the Yankees’ best all-around player during his career year in 2018, which resonates within GM Brian Cashman’s front office. The Yankees can make him a $17.8 million qualifying offer, which he could very well take given the dearth of teams looking to spend money on a shortstop this offseason.

Should Gregorius hold firm for the desire to sign a multiyear deal, the Brewers are one of the few contenders that could upgrade at shortstop.

While his half-season following Tommy John surgery resulted in solid power (16 home runs, 61 RBIs in 82 games), his .276 on-base percentage was a career low and his .238 average was the lowest of his five years in New York.

Though some view his power as a product of Yankee Stadium, Gregorius’ numbers in 45 road games (.840 OPS, 10 home runs) dwarfed his home stats in 37 games (.570 OPS, six home runs). The Yankees can slide Gleyber Torres to shortstop and DJ LeMahieu to second base, lessening the need to bring Gregorius back if his demands are too high for their taste.

Optimistic view: “He should make a lot of money from a team looking for a plus defender with an above-average offensive bat,” an NL talent evaluator said. “I think either way he makes a lot of money, but the best case for him is to keep the Yankees involved.”

Pessimistic view: “He chose a bad time to have a bad year,” the executive said. “His best interest might be to take a one-year deal, play a healthy season and hit the market again. If he gets the QO, he should jump at it.”

Mike Moustakas, 2B/3B

Free agency has not been kind to Moustakas the past two years. A rejected qualifying offer led to a winter of job-hunting prior to the 2018 season, though he ultimately re-signed with the Royals for just one year at $6.5 million.

Moustakas was traded to Milwaukee that season, but even with no qualifying offer to deal with, he and agent Scott Boras were unable to land the multiyear deal they sought, agreeing to a one-year, $7 million deal (plus a $3 million buyout on an $11 million mutual option) with the Brewers.

What if Moustakas and Boras encounter the same issues as last offseason? Sources said the infielder was seeking a multiyear deal worth between $50-80 million, though he settled on a fraction of that in a one-year contract.

“How he’ll do could depend largely on his agent,” an AL exec added, referring to Boras. “What did they learn from the past two years? The qualifying offer affected him the first year, but they had the same situation last year. Maybe this is the year they find the sweet spot.”

Moustakas made his third All-Star team in five years this season, posting a career-high .845 OPS despite a modest .329 on-base percentage. His 35 homers give him 101 over the past three seasons, though that has come with a .319 OBP.

Optimistic view: “He’s coming off a much better year than last year,” an AL executive said. “It’s tough, because we’ve seen what’s happened with him the past two years, so what will he be looking for? He should get a three-year deal. A team that likes Moustakas is focused on the power and the makeup, while a team that doesn't like him as much is focused on the lower on-base percentage. I don’t think anyone can strongly dislike the player, but the question is the value.”

Pessimistic view: “The worst case is he has another offseason like he’s had the past two years,” an NL executive said.

Zack Wheeler, RHP

Wheeler has been solid in back-to-back seasons leading up to free agency, pitching to a 3.65 ERA (3.37 FIP) over 377 2/3 innings in 60 starts in 2018-19. His strikeout rates have increased in each of those seasons (nine per nine innings in 2019) while his 2.3 walks per nine this season represented a career best.

Although he’s not in the same class as Gerrit Cole or Stephen Strasburg, Wheeler is considered by most to be one of the five best starters in this free-agent class.

One NL executive believes Wheeler’s free agency will come down to “risk tolerance,” citing his injury history. Wheeler missed the 2015 and ’16 seasons following Tommy John surgery, then battled other arm issues in '17 and spent time on the injured list this summer with shoulder fatigue. Though it should be noted he has topped 180 innings in each of the past two seasons and ranks 12th in MLB in combined innings pitched over the last two years.

The qualifying offer -- which the Mets seem almost certain to offer to Wheeler -- could also complicate the pitcher’s free agency the way it did with both Dallas Keuchel and Craig Kimbrel last offseason -- “He’s going to get one and I think it hurts him because he’s not in that top tier,” an AL exec said.

Optimistic view: “He’ll find a team that is willing to bet on him and his upside,” an NL talent evaluator said. “Given some of the things that he’s been able to do very well in ‘18 and ‘19, he should get a multiyear commitment that will pay him very handsomely.”

Pessimistic view: “Teams that feel like they’re contending and are an arm away night take a shot on him and be more aggressive,” the NL executive said. “But I could see half the league saying, ‘We’re not touching those medicals.’ It depends on what your rotation looks like and what money you have to spend. He can be really good; we’ve all seen that. The downside for him is just the health standpoint.”