In any other year, this would be a boon time for teams looking to sign a shortstop.

The headlining shortstops of this winter’s free-agent class in Didi Gregorius, Marcus Semien and Andrelton Simmons might represent three of the 10 best players at that position dating back to 2017, and yet every general manager in the game can recite the five superstar shortstops (Javier Báez, Carlos Correa, Francisco Lindor, Corey Seager and Trevor Story) who could all hit the market a year from now. Some teams might prefer to wait until then (and they might also take a long look at KBO free agent Ha-seong Kim), but that means there’s an opportunity for clubs in dire need of a shortstop -- the Reds, Rangers, Brewers and Angels all come to mind -- to take their shot now and get an established veteran, likely at a discount compared to ‘21’s super-class.

Gregorius, Semien and Simmons have all experienced some highs and lows in recent years, so here are some of the pros and cons for each that front offices will be weighing.

Didi Gregorius

Pros
In one sense, Gregorius is nearly a unicorn in that he and Seager are about the only power-hitting shortstops who hit from the left side. Gregorius’ lefty swing has found plenty of seats in right field for the Phillies and Yankees; pull happy or not, Story and Lindor are the only shortstops with more homers than Gregorius’ 98 since the start of his breakout 2016 season. He enjoyed a better ‘20 campaign than Semien and Simmons, putting up a 116 weighted runs created plus (wRC+, where 100 represents league average) and looking a lot like the hitter who flourished in the Bronx before undergoing Tommy John surgery.

Cons
Gregorius was a stud at Philadelphia’s Citizens Bank Park (131 wRC+) and average everywhere else (100 wRC+), and that largely tracks with his Yankees tenure, too. Home ballparks probably need to be part of the equation when evaluating Gregorius and his extreme pull-side power. If your club’s park doesn’t have a friendly short porch in right, you may need to temper power projections -- especially because Gregorius has always ranked poorly on Statcast’s average exit velocity and hard-hit-rate leaderboards, despite the dingers.

Maintaining that offense is crucial for Gregorius, because he also rates as a poor defender by Statcast’s infield Outs Above Average metric on a perennial basis.

Marcus Semien

Pros
Semien is only one year removed from having a claim as one of the very best players in baseball; he finished third in the 2019 American League MVP Award voting and he was fifth across the Majors in FanGraphs’ version of WAR (7.6). If one bundles together total WAR from 2019-20 combined to account for this year’s shortened season (as we have on MLB’s position-by-position free-agent list here), Semien owns the highest two-year fWAR total of any available free agent at 8.8. He was also a respected clubhouse leader in Oakland and very durable, missing fewer than seven games in all but one of the past six seasons.

Cons
That combined two-year fWAR total is overwhelmingly skewed toward 2019, because Semien took some baffling steps back in ‘20. His average dropped to .223 and he slugged just .374 after topping .500 for the first time in his career the year before, with his overall 213-point OPS decline ranking among the 25 biggest year-to-year drops from 2019 to '20. Perhaps even more concerning was the apparent regression in Semien’s defense, a fundamental aspect of his ascension in ‘19 that fell off according to both the defensive runs saved (DRS) and ultimate zone rating (UZR) metrics (Statcast’s OAA didn’t rate Semien well in either season). Semien played through a side injury that eventually sidelined him in early September, making his case even trickier to evaluate. Teams have to figure out if Semien can replicate the heights of his ‘19 campaign, or whether ‘20 was a return to his truer median form.

Andrelton Simmons

Pros
As one of the very best defensive shortstops in modern history, Simmons is the only one of these free agents who has been consistently elite on either side of the ball. He’s a four-time Gold Glove Award winner and won the 2013 Platinum Glove, which is given to the best overall defender in each league. While defensive metrics are far from perfect, especially the farther back in history one goes, Simmons’ 191 career defensive runs saved is more than any other shortstop on record -- and it’s not particularly close.

Simmons’ elite glove has helped him stay valuable despite struggles on offense, but there is one batting skill at which he’s elite: Simmons led all qualified hitters in strikeout rate in 2019, and he ranked in the 95th percentile in ‘20. If you’re looking to improve your lineup's contact ability, he’s an excellent option.

Cons
All those balls in play haven’t equaled offensive production. After a couple of surprising power seasons that helped him earn down-ballot AL MVP votes in 2017-18, Simmons regressed to a well-below average hitter in 2019-20 (.362 SLG, 82 OPS+).

That might be a return to Simmons’ career baseline at the plate, and that places a lot more pressure on his defense. The 2020 season is a little concerning when viewed through that prism; Simmons actually finished as a below-average defender by Statcast OAA, and DRS and UZR didn’t rate him favorably either. Teams could very well toss that out as noise from an extremely short season (Simmons tied for MLB’s second-best infielder by OAA in 2019), but that rare defensive slip was unfortunate timing for a 31-year-old shortstop entering the free-agent market.