When the Boston Red Sox take the field on Tuesday to begin a three-game series against the Oakland Athletics, they'll do it with the peace of mind that comes with possessing the majors' largest division lead. The Red Sox, who entered the spring presumed to be the third- or fourth-best team in the American League East, instead lead the New York Yankees and Tampa Bay Rays by three games apiece, a product in part of winning four of their last five contests.

While the season is too young to take its results at face value, mid-May is often when the re-evaluation process begins. Enough time has passed for team-level results to have an impact on the final standings. For example, the Red Sox's hot start (22-14, or a 99-win pace) means that playing .500 ball from here out would leave them with an 85-77 record. Four "banked" wins may not seem like much, but it can make the difference when a team is deciding what to do at the trade deadline, or when a team finds itself in a tight playoff race.

With that in mind, it's time to start asking: are the Red Sox a legitimate playoff contender? Here are three factors that lead us to believe the answer is yes.

We mentioned the "banked wins" concept above, but the Red Sox have other reasons to feel optimistic about their first 36 games. Run differential, or runs scored minus runs allowed, often holds greater predictive value in small samples than a team's win-loss record.

The Red Sox, who have bested their opponents by 33 runs this season, have the second-best per-game run differential in the majors, trailing only the Chicago White Sox. The Red Sox rank first or second in the AL in batting average, on-base percentage, and slugging percentage, and lead the majors in runs scored. Their offensive potency can't be credited solely to Fenway Park's generous dimensions, either: they rank second in the majors in wRC+, or FanGraphs' park-adjusted offensive metric that properly weighs the value of getting on base.

It may be tempting to credit Boston's success to a lean schedule -- after all, the Red Sox are coming off a stretch that saw them play the Baltimore Orioles, Detroit Tigers, and Texas Rangers … or three probable last-place teams -- yet that isn't the case, according to Baseball Reference's calculations. Not only has Boston played a middle-of-the-road slate, but it has performed better against good teams. Entering Tuesday, the Red Sox had the majors' best winning percentage against clubs with at least a .500 record (10-5), whereas they're just 12-9 against losing teams.

Some of the above is descriptive instead of predictive -- or more indicative of what has happened rather than what will happen -- but the Red Sox nonetheless have several statistical characteristics that tend to be associated with good teams.

No team is perfect. All any front office can hope for is that their club's issues can be addressed through in-season trades and internal promotions. The Red Sox are decently positioned in that respect, thanks in part to a solid core of hitters that includes Xander Bogaerts, Rafael Devers, and J.D. Martinez. Of course, that doesn't mean they're without some obvious weaknesses.

As constructed, the three areas of concern for Boston are its outfield, first base, and pitching staff. Save for Alex Verdugo and the injured Enrique Hernández, the Red Sox have received minimal production from their outfielders. Maybe Hunter Renfroe or Franchy Cordero can turn around their seasons, but their performances to date leave the outfield on the needs list. Ditto for the cold corner, where Bobby Dalbec has so far failed to build upon last year's success.

Conversely, Boston's pitching staff has so far produced more value than expected, as both the rotation and bullpen are in the top half of the league when their ERAs are adjusted for ballpark. The catch is that it's hard to feel comfortable about a rotation that includes Nathan Eovaldi, Nick Pivetta, Garrett Richards, and Martín Pérez -- each an attrition risk for either performance and/or health reasons. Meanwhile, almost every contender wants to add an extra reliever or two at the deadline, so there's nothing notable about Boston or its bullpen in that respect.

Who, exactly, the Red Sox might pursue at the deadline is unknowable at this point. Based on their current situation, though, they wouldn't necessarily need to land a top-of-the-market player, like a Max Scherzer or a Joey Gallo, to secure an upgrade. Splurging for a star is always the sexiest and highest-impact route, but the Red Sox might find themselves in a position where they're improved merely by replacing a subpar contributor with a league-average one.

The Red Sox don't have to rely on the trade market alone. While they don't have a top-notch farm system -- Baseball America ranked them 20th — they do have a number of contributors nearing the Show.

On the hitter side, that group includes infielder Jeter Downs and outfielder Jarren Duran. Downs, arguably the key piece in the Mookie Betts return, profiles as a solid starter at the keystone thanks to his assortment of average and solid-average tools. Duran, on the other hand, has plus-plus speed and has unlocked more of his raw power by altering his swing. Both could give the Boston lineup a boost between now and the end of the regular season.

The pitching side of things won't be as fruitful. Three of Boston's top pitching prospects -- Bryan Mata, Tanner Houck, and Connor Seabold -- are out injured, with Mata scheduled to miss the season following Tommy John surgery. As such, the Red Sox's chances at an internal rotation boost might hinge on how veteran left-hander Chris Sale recovers from his own elbow surgery.

Sale recently threw off a mound for the first time since undergoing his operation last March. It's unclear if he'll be able to return before the All-Star break, or how much he'll realistically contribute.

A lot can happen between now and the trade deadline, let alone the end of the season. Even so, the Red Sox should be encouraged by their hot start and the state of their roster. There's enough uncertainty with their pitching staff to think things could fall apart over the coming months. As it lays now, however, the Red Sox look like they should remain a legitimate contender for a playoff berth, even if the Wild Card Game still seems likelier than a division title.