Last week's 5 biggest fantasy surprises: Is Nick Castellanos finally fixed?

Fantasy managers dreamed for more of the same from Nick Castellanos when he signed with the Philadelphia Phillies. Despite leaving the hitter-friendly Great American Ball Park, Castellanos found himself in an equally power-friendly Citizens Bank Park. It seemed he was destined for another tremendous offensive season, right?

Things haven't worked out that way. Castellanos has been one of fantasy's most disappointing performers, though he did show signs of life last week, hitting .278 with 2 home runs.

Fantasy managers who held on to Castellanos at the trade deadline need him to recapture his old form to live up to his draft status. If he can turn things around, his bat is strong enough to propel fantasy managers up the standings in the final months of the season.

Ranks are based on standard Yahoo fantasy leagues

Nick Castellanos, Philadelphia Phillies OF

Fantasy rank over the last seven days: 32

Season-long fantasy rank: 182

It's too early to tell whether Castellanos has completely turned things around. His numbers are strong in August, but it's been just six games. If you're hoping this is the start of a monstrous second-half surge, however, watch Castellanos' plate discipline in the next couple of games.

Castellanos has chased a lot more pitches out of the zone this season. His chase rate sits at a career-high 44 percent. This is possibly a sign of nerves. Castellanos is with a new team for the first time in his career. Players who switch teams typically see higher than normal chase rates early in their tenure, probably because they are anxious to get off to a good start in front of their new teammates and fans. Catcher J.T. Realmuto talked about that in July when referencing Castellanos' struggles.

There are other issues with Castellanos to be aware of as well. His fly-ball rate is lower than normal and he's not hitting the ball as hard. It's possible those issues are linked to his high chase rate. It's also possible his swing is off.

Castellanos hasn't experienced any major skill regression, however, so this probably isn't an age-related decline. He can still have a huge second half — but only if he stops chasing pitches out of the zone.

Ryan McMahon, Colorado Rockies 2B, 3B

Fantasy rank over the last seven days: 5

Season-long fantasy rank: 245

Fantasy managers have waited for a breakout from Ryan McMahon for years now. Though he showed some promising signs last year, it still hasn't happened.

Things haven't gone well for McMahon this season, but that doesn't mean he hasn't done some encouraging things. He's barreling the ball at a good clip, his average exit velocity is up and his walk rate has taken a step forward.

Despite that, McMahon's numbers are still middling. Some of that has to do with his launch angle. McMahon's launch angle is down about three percent compared to last season, which could explain his poor power numbers. While his plate discipline has improved, McMahon has taken things too far. His swing rate on pitches in the zone is down nearly 10 percent. He's letting too many strikes go by unpunished.

A slightly more aggressive approach might be necessary. McMahon is doing some promising things when he makes contact, but he's not capitalizing on pitches in the strike zone.

Expecting a massive breakout is foolish at this point. McMahon still has issues with breaking balls and off-speed pitches. There's a chance his numbers improve in the second half, but it's hard to project a major step forward even if he's made some encouraging tweaks.

José Suarez, Los Angeles Angels SP

Fantasy rank over the last seven days: 10

Season-long fantasy rank: 567

It's easy to doubt a pitcher who hasn't impressed after multiple stints in the majors. Third time might be the charm, however, for Los Angeles Angels starter, José Suarez.

Suarez had some moments last season, but has mostly looked like an uninspiring starter on an uninspiring team. Even this year, you can look at his numbers and conclude he's bound for more of the same. That's probably the smart thing to do.

But Suarez has changed one thing this season, which might be responsible for his newfound success. He's introduced a slider to his repertoire that's led to strong results. The pitch has a 31.7 percent whiff rate, second to Suarez's changeup. The emergence of the pitch has fueled Suarez's 22.4 percent strikeout rate. The slider has also allowed Suarez to cut down on his fastball usage. Batters are hitting .312 against his fastball this season. They are hitting just .172 against his slider.

Suarez appears to have found his stride after some middling starts early in the season. He hasn't given up a run in his last three starts. He's struck out 16 batters in 17 1/3 innings over that period.

There are still reasons to be concerned, however. Suarez's walk rate and strikeout rate are both high. He also appears to be on a strict pitch count. But if he can turn in 1-2 more strong starts, fantasy managers shouldn't completely write off his performance. That slider makes him an intriguing player to monitor.

Yordan Alvarez, Houston Astros OF

Fantasy rank over the last seven days: 581

Season-long fantasy rank: 10

Even the best hitters in baseball are subject to bad weeks. Houston Astros slugger Yordan Alvarez has struggled to open August, but it shouldn't be a cause for concern. Everything about his first-half breakout is legitimate, and we just want to celebrate his performance thus far.

All the promise Alvarez showed last season has been taken to a higher level in 2022. His plate discipline is superb. His 14.9 percent walk rate is among the best in baseball and he's striking out under 20 percent of the time, a rare figure for a slugger.

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He's also been extremely stingy with pitches out of the strike zone. Alvarez has cut his chase rate by nearly five percent. He's laying off pitches outside the zone and swinging more at pitches he can handle. When he's making contact, he's hitting the ball hard. His average exit velocity is 95.8 mph, the best among qualified hitters. He's also maximized his power output by pulling the ball more.

For season-long players, don't panic about a bad week. Alvarez should be excellent the rest of the year. For dynasty players, Alvarez is an ascending player. As long as he stays healthy, he should continue to produce like one of the best hitters in baseball.

Graham Ashcraft, Cincinnati Reds SP

Fantasy rank over the last seven days: 56

Season-long fantasy rank: 582

Cincinnati Reds starter Graham Ashcraft turned in two strong starts last week, making him a surprise top-60 player in fantasy baseball. Is he worth a speculative add the rest of the way?

The short answer is: Not yet.

Despite some excellent velocity, Ashcraft hasn't seen his stuff translate to strikeouts yet. His 15 percent strikeout rate would rank as one of the lowest in the league among qualified pitchers. In his two most recent starts, Ashcraft had only 6 strikeouts in 14 innings.

But his skillset is worth monitoring. Ashcraft averages 97.2 mph on his cutter. He also features a power sinker that comes in at 96.8 mph. Hitters tend to pound that pitch into the ground, giving Ashcraft a 52.6 percent ground ball rate. His slider looks like a good out pitch and has a 28.5 percent whiff rate.

How does a pitcher with that stuff only strike out 15 percent of opposing hitters? There's exciting fantasy potential here if Ashcraft can figure that out. Throwing more pitches out of the zone could help. Ashcraft has a tiny 5.5 percent walk rate. That's a good thing for most pitchers, though Ashcraft could have success trying to get hitters to chase.

For now, Ashcraft probably isn't worth a speculative add in most fantasy leagues. But the instant he puts together a few consecutive starts with high strikeout numbers, he's worth another look.