The first half's five biggest fantasy surprises: Will Nestor Cortes remain an ace?

There might not be regular-season baseball games during the All-Star break, but fantasy managers can never rest. The All-Star break gives us an opportunity to perform a deep evaluation of our teams before the trade deadline.

Will that breakout star really keep it up or should they be traded for a struggling ace poised to turn things around? Those decisions could make or break your fantasy season.

The 2022 MLB season has provided plenty of surprising developments. Sandy Alcantara has a legitimate argument for National League MVP and, despite calling Denver home, Kris Bryant hit his first home of the season in July.

Here are a few other players who deserve attention for their shocking first-half numbers.

Ranks are based on standard Yahoo fantasy leagues

Nestor Cortes, New York Yankees SP

Fantasy rank in the first half: 52

Preseason fantasy rank: 157

Gerrit Cole is still the ace of the Yankees, but Nestor Cortes is the team's biggest fantasy bargain. Cortes was ranked 157th to start the year and has pitched like the 52nd best player in fantasy thus far. Perhaps managers should have seen this coming. Cortes showed glimpses last season, posting strong strikeout and walk rates and a 2.90 ERA over 93 innings.

Those figures have mostly carried over to 2022. Cortes is whiffing over a batter per inning and has one of the lowest walk rates in baseball. Home runs remain a concern for Cortes, but he did work on the issue. He remains a fairly extreme flyball pitcher, but he did slightly increase his ground-ball rate from 27.4 percent to 32.3 percent this season. It's not much, but it is helping.

Those numbers on their own provide hope that Cortes can keep this up moving forward. But there's even more evidence to suggest he's an emerging ace. Cortes really worked on his cutter over the offseason. Batters hit .271 against the pitch last season, but are hitting just. 184 against it in 2022. His velocity and whiff rate have increased on the pitch. Most importantly, Cortes and the Yankees realize all of this. He's using the pitch 12 percent more often than he did last season.

As long as fatigue isn't an issue down the stretch, Cortes should continue to put up excellent numbers for fantasy managers in the second half.

Javier Báez, Detroit Tigers SS

Fantasy rank in the first half: 577

Preseason fantasy rank: 67

Javier Báez has always had a small margin for error. His approach — swing often and swing hard — resulted in dominant stretches when he was going well and miserable lows when he wasn't. On the surface, it appears Báez can no longer maintain the high-wire act. He's hitting just .213/.251/.375 in 78 games.

Javier Báez with the Tigers hasn't been a fantasy wunderkind
Javier Báez has been a big fantasy disappointment. (Photo by Duane Burleson/Getty Images)

Báez loves to work in the extremes. He rarely walks and he strikes out a ton. That's what fuels his volatile approach. Oddly, though, strikeouts haven't been a problem for him in Detroit. Báez's 23.8 percent strikeout rate is actually a career low, suggesting he may have altered his approach to be a more consistent player. His contact rate is up eight percent on pitches in the strike zone and his swinging-strike rate is down to 18.8 percent, an average figure for Báez.

Those numbers would typically suggest positive regression for Báez. Problem is, the new approach has come with a significant drawback: He's not hitting the ball hard anymore. His hard-hit rate dropped from 45.2 percent last season to 34.1 percent in 2022. His average exit velocity is in the 22nd percentile, a ghastly number for a player who has excelled due to his ability to hit the ball with authority.

Báez missed time in April due to a thumb injury and it's possible that issue has lingered, preventing him from hitting the ball hard. If he can get healthy, if he can rip it again, better things are ahead. But if the thumb continues to be an issue or if the new approach is geared toward more contact over power, things could remain rough moving forward.

Dansby Swanson, Atlanta Braves SS

Fantasy rank in the first half: 12

Preseason fantasy rank: 123

Dansby Swanson has already been covered in this series. On May 31, we said Swanson's hot stretch was fluky and that he would make for a strong trade candidate.

Oops. Instead, Swanson has continued to mash, hitting .294/.353/.481. By fWAR, this is already the finest season of his career.

The same concerns we had then are present now. Swanson is reaching for more pitches and not making as much contact out of the zone. His swinging-strike rate is a career-high, which should result in a lower average. His .374 BABIP is actually higher than it was in May, when we confidently said, "Swanson's .367 BABIP is due for regression."

Clearly, Swanson is doing something right. Both his average exit velocity and hard-hit rate are up, which is helping to fuel his strong start. He's also elevating the ball more, a positive development for a player who has always hit the ball hard. After being an extreme pull hitter last year, he's using the whole field more, making Swanson less predictable for defenses.

And yet ... it's really hard to see this continuing. The BABIP and contact issues suggest Swanson can't keep producing at this level. If regression hits, he should still be a solid fantasy contributor, so managers don't have to deal Swanson at the deadline. But if a leaguemate is desperate or offers a trade involving a star player bound to bounce back, managers should make that deal.

Tyler Mahle, Cincinnati Reds SP

Fantasy rank in the first half: 681

Preseason fantasy rank: 139

Other than Lucas Giolito, who we still think will improve, Tyler Mahle has been the most disappointing starting pitcher this season. Through 92 1/3 innings, Mahle has a 4.48 ERA and a 1.30 WHIP.

Those are poor numbers, but things seem to be on the upswing. Mahle already has made some corrections and has a 3.50 ERA over his last 10 games. During that period, he's produced seven quality starts, a significant number for Mahle, who sometimes struggles to go deep into games.

Mahle definitely dealt with some bad luck early in the season. His 68.5 percent strand rate remains really low. Mahle posted strand rates of 75 percent or higher in each of the past two seasons, suggesting that figure will rebound as the season continues. Despite losing some velocity, his fastball remains strong. Batters are hitting just .200 against the pitch, making it Mahle's best weapon.

Tyler Mahle with the Reds.
Tyler Mahle could be in for a strong second half. (Photo by Thearon W. Henderson/Getty Images)

At the same time, there were some genuine reasons for concern. Mahle's breaking pitches have all been awful. He's given up batting averages over .310 on both his slider and cutter. The slider remains a high-risk, high-reward pitch. It has a great 34.4 whiff rate when he hits his spot, but a .311 batting average against when it gets too much of the plate.

It's possible Mahle has already fixed those issues. His recent stretch suggests he's identified and worked on some of the things holding him back. He did go on the Injured List with a shoulder injury in early July, though it's believed to be minor. His recent success suggests that's the case as well, but you never want to see pitchers experience shoulder injuries.

Mahle probably doesn't have a ton of value on the fantasy trade market considering those factors. But if the shoulder injury is minor, he could be in for a solid second half.

Luis Arraez, Minnesota Twins 1B, 2B, 3B, OF

Fantasy rank in the first half: 88

Preseason fantasy rank: 294

Luis Arraez has been a revelation for the Twins in the first half. His .338/.411/.445 line resulted in Arraez making the All-Star team for the first time. It was a deserving honor for the player leading the American League in average and on-base percentage.

Arraez has always shown strong contact skills and posted high batting averages in the past. The thing that has set him apart this year is power. It's not so much his ability to hit home runs, though he's already set a career high with 5; it's more Arraez's ability to leg out extra-base hits.

It looks like a safe bet to continue. Arraez is hitting the ball much harder this season. His 89.1 average exit velocity is a career-best and puts him in the 51st percentile. That doesn't sound impressive, but it makes a big difference for a guy previously viewed as a slap hitter. Both his barrel rate and hard-hit rate have improved. Compared to the rest of the league those numbers are also not impressive, but given Arraez's skill set, the improvements stand out more.

There's very little to suggest this is going away. Arraez was always a high-contact, high-average hitter. He managed to retain those gains while also adjusting his swing to do more damage. Arraez may never hit 15 home runs in a single season, but 10 home runs and a .330 average will play in any fantasy league.