When it comes to charting the course of a club's season, there are really just three types of players: the ones who disappoint against performance projections, those who solidly meet the head coach's ask and the guys who roll expectations up into a ball and fire it into the top corner.

As we make the MLS midseason turn, let's honor the players who've gone the farthest above and beyond so far.

There was little noise made when New England snagged the 24-year-old defensive midfielder from La Liga 2 side Gimnastic. Zahibo has ably stepped in to guard a sometimes shaky backline for one of the league's surprise teams. The tackle-happy deterrent has given the Revs more freedom to harass foes with a high press, as well as a greater ability to go toe-to-toe with the East's top four teams.

The San Jose Earthquakes forward has always been known as a guy to get into great positions, only to disappoint too often on the finish. In his first season with the Quakes, Hoesen put a meager 34 percent of his shot attempts on target, and buried just 7 percent of them to end up with five league goals.

This year, he's on frame 43 percent of the time and scoring on 18 percent of his efforts. He's also firing exactly 50 percent more shots per game over last season, which is why he's already scored (a top-flight career high) 10 goals in about 400 fewer minutes played. Hoesen has both of San Jose's winners and a pair of game-tying goals, so imagine where they'd be without him.

Plenty of observers gave a thumbs-up to Columbus Crew SC's offseason Young Designated Player signing. I doubt anyone thought Valenzuela would be a Best XI contender by July, but here we are. The teenage left back has been better than advertised at both ends.

Most importantly, in a system that relies heavily on its wide backs to drive play up the flank, he's offered the vital balance that prohibits opponents from shading over to crowd Harrison Afful.

Russell (at left) and Salloi | USA Today Sports Images

One's a veteran newcomer from Scotland, one's a Homegrown Player breaking out at 21. Most often used as bookend wingers, they come as a package deal on this list because their drive and production has Sporting KC atop the West with little scoring from the center forwards on the roster.

Russell challenges every defender, earns dangerous dead-ball looks, and has five goals to go with as many helpers. Salloi has five goals (two of them second-half winners) and six assists (half of which set up late deciders). Russell runs 'em wobbly and Salloi finishes 'em off.

Probably the most obvious Comeback Player of the Year candidate is the Columbus striker, who has rediscovered his true game after bring chained to the No. 9 position by Gregg Berhalter. For Zardes, who suffered the indignity of right back shifts in his final three LA Galaxy outings last year, it's like 2014 all over again.

He's got 11 goals in 19 games, and it's all about volume. Zardes is seeing more good chances than he has in his career, and has been sticking them home since opening day. He's hitting at almost an identical rate to that 16-goal campaign with the Galaxy from four years ago as Berhalter continues to work his magic with center forwards.

Surely, we all can recall the concerns over who would key the New York Red Bulls attack with Sacha Kljestan gone in a trade. After a long transfer saga, Alejandro Romero Gamarra – better known simply as Kaku – finally arrived to New York highly-rated. Even so, no one expected him to be two up atop the MLS assist chart at the season's turn.

The 23-year-old has two second-half winners among three goals to go with his 10 assists, but one can't reduce his impact to mere counting stats. Kaku has also done so much of his damage from the wide channels, simultaneously pulling attention away from both the Red Bulls' ever-encroaching fullbacks and the scrappy bunch making plays up the gut.

Being well-acquainted with the forward from his time at Stabaek, I figured he'd fare pretty well in MLS. However, nobody could imagine he'd instantly go crazy, bagging seven goals in his first 298 minutes for LAFC.

Perhaps we all should have seen it coming, though; Diomande has scored 32 times in 32 career appearances under current boss Bob Bradley. Though he may have the shortest season run of this particular bunch, the striker currently inspires the most fear in opponents by a wide margin. Let's see how much of this record goal pace he can maintain.

The Columbus center back's performances were oft-derided during his debut MLS campaign, which he freely admitted was for just cause. A DP signing with World Cup experience, arriving in his prime, Mensah committed a shocking rash of gaffes, and always seemed to have his mistakes punished.

Consider it all a learning process, as Mensah has enjoyed a complete form reversal this season. He's been large and in charge for a Crew SC side allowing just 10 shot attempts and one goal per game, both league lows. The Ghana international has never been so careful with moving the ball forward and stands chief among the reasons a team that leans on the front foot so faithfully has only leaked one counterattack goal in 19 games.

We're back with another double pick, but this one's a different type of duo. Penilla and Turner, each of whom made his MLS debut this season, are the key men at the front and the back of Brad Friedel's Revs re-mold.

Penilla turns up everywhere in the final third, running suddenly set-upon defenders ragged to the tune of eight goals and five assists. Turner is the surprise award candidate in goal. The 24-year-old is fourth in the league with 60 saves and has two nods in he MLS Team of the Week presented by Audi. These two are the main reasons New England are 5-2 in one-goal decisions after going 1-5 in that category over the first half of 2017.

With Jack Harrison gone to Middlesbrough, New York City FC entered the season in search of at supplemental offense to aid David Villa. Jo Inge Berget is starting to cash in and young playmaker Jesus Medina has had his moments, but the man who provided what NYCFC needed from the word go is the one who arrived with easily the lowest expectations.

Tajouri-Shradi scored the winner in his first start, netted both equalizers to earn a road draw in his second and has barely slowed down since. He came with the rep of a guy with great wheels who could push tempo and make plays at speed. Surprisingly, the winger has also been a ruthless finisher, needing just 17 shots to ring up eight goals (tied for the team lead) in 823 minutes.