Last week's five biggest fantasy surprises: Is Anthony Rizzo's resurgence real?

Anthony Rizzo's first taste of New York was fine. After being traded from the Chicago Cubs at the trade deadline, Rizzo put up basically the same exact numbers with the New York Yankees he did as a Cub. He did not take advantage of the team's short right-field porch as much as expected, posting a lower slugging percentage once he got to New York.

That's all changed in 2022. Rizzo has mashed 19 home runs — just three short of last year's total of 22 — in 66 games. It took an offseason, but it looks like Rizzo tailored his swing to fit his new home.

With that said, Rizzo is 32. Can fantasy managers really trust him to set a new career-high in dingers, or has his first-half power surge been fueled by nothing more than luck?

Ranks are based on standard Yahoo Sports fantasy leagues

Anthony Rizzo, New York Yankees 1B

Fantasy rank over the last seven days: 1

Season-long fantasy rank: 20

It's easy to look at Rizzo's home run distribution and assume the power surge is a result of playing home games at Yankee Stadium. All but one of his 19 home runs have been pulled to right field.

Rizzo's expected home run data shows he would have fewer home runs if he played in a different home park, though not by a huge amount. He would have 17 home runs if he played at Progressive Field, which is a slightly below-average park for home runs, for example. He would have 12 home runs at Oracle Park, but that's an extreme environment for lefties.

Playing half his games in Yankee Stadium certainly helps, but Rizzo deserves credit for altering his approach to fit his new home park. He's decided to sell out for power, posting an extreme fly-ball rate and pulling the ball a career-high 50.3 percent of the time. The benefits of that approach should be pretty obvious. In Yankee Stadium, hard-hit fly balls to right field have a strong chance of turning into home runs.

The major downside of Rizzo's approach has to do with his batting average. Hitting fly balls at such an extreme rate can lower batting average and BABIP. Those fly balls that wind up short of the stands usually get caught.

Don't expect Rizzo's .238 average to rebound much, but the power surge looks real.

Andrew Vaughn, Chicago White Sox 1B,OF

Fantasy rank over the last seven days: 19

Season-long fantasy rank: 153

After a middling rookie season, Andrew Vaughn is delivering on his promise.

Vaughn is hitting .330/.381/.505 in 48 games. His breakout has been one of the biggest surprises of the 2022 MLB season — but should fantasy managers buy into it?

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Even during his disappointing rookie year, Vaughn showed some promising signs. He hit the ball hard consistently, and had an elite max exit velocity, which indicates a strong power ceiling. He was held back by ... being a rookie and seeing major-league pitching for the first time in his career. Vaughn posted a slightly below-average whiff rate as a rookie and was extremely vulnerable to breaking pitches.

It's cliché to say it, but Vaughn looks like he learned how to hit during the offseason.

He made the necessary adjustment on secondary offerings and is hitting .273 against breaking balls and .368 against offspeed pitches. Vaughn hit .164 and .214 respectively against those types of pitches as a rookie. Vaughn posted good numbers against fastballs last year, but he's obliterating them in 2022; he has a .365 average against heaters. He's cut down drastically on his whiff percentage, turning it into one of his biggest strengths.

Vaughn's barrel rate is down and he's still willing to chase sliders out of the zone, but there's more than enough evidence to suggest he's made major strides as a hitter. After beginning the season in the No. 7 spot in the order, Vaughn is now the White Sox's No. 2 hitter, a sign Tony La Russa and the front office believe Vaughn is the real deal.

Nick Pivetta, Boston Red Sox SP

Fantasy rank over the last seven days: 17

Season-long fantasy rank: 84

Long-time fantasy managers know there are three constants in life: Death, taxes and talking yourself into Nick Pivetta after two good starts.

That's not exactly what's happening this time around. Pivetta's sample size is much larger than two games; his last nine starts have been excellent. He has a 1.77 ERA and has struck out a batter per inning over his last 61 frames.

Pivetta's fastball appears to be the driving force behind his success. Batters are hitting just .156 against Pivetta's four-seamer this season. Batters hit .255 against the pitch in 2021 and .286 against it in 2020.

It's tough to pinpoint how the pitch has improved. His spin and whiff rates with the fastball are unchanged since last season. The pitch has slightly more vertical movement and slightly less horizontal movement, which could explain some of the success. Pivetta also appears to have better command with the pitch. He's done a better job keeping the ball high and inside against righties and high and outside against lefties. Those are positive developments, but they probably don't fully explain how Pivetta's fastball has been so dominant.

Even if the pitch is improved, there's probably going to be some regression in Pivetta's numbers. A .156 batting average against a fastball is likely to rise, as is his low 8.3 percent home run per fly-ball rate. Pivetta is allowing more fly balls this season but is on pace to give up far fewer home runs. He's still giving up a lot of hard-hit balls and a high average exit velocity, suggesting the low home run rate is bound to rise.

Fantasy managers have seen this before from Pivetta. He looks good for a few starts but fails to sustain that success. Pivetta may be a better pitcher this time around, but regression still seems inevitable.

Charlie Blackmon, Colorado Rockies OF

Fantasy rank over the last seven days: 13

Season-long fantasy rank: 74

If Rizzo can put up career numbers at an advanced age, maybe Charlie Blackmon can too. The 35-year-old Blackmon is hitting .270/.326/.471, with 11 home runs, in his first 60 games in 2022.

The power numbers are the big surprise, as Blackmon slugged just .422 between 2020 and 2021. If his 2022 power surge is real, he could have a shot at jumping back into No. 2 outfielder territory.

Unlike Rizzo, however, it looks like Blackmon will have a tough time keeping this up.

Most of his indicators are heading in the wrong direction. His average exit velocity is a career-low 85.5 mph and his hard-hit rate has declined to 32.5 percent. In addition to that, he's striking out more, walking less and reaching at more pitches out of the zone. Those are troubling signs for an aging hitter.

Despite those changes, Blackmon is making more contact and his swinging strike rate remains stable, offering hope he can still hit for a decent average. The power remains a bigger question. His 11 home runs are, for the most part, earned if you look at his expected numbers. But Blackmon's indicators suggest it will be hard for him to maintain this pace.

Craig Kimbrel, Los Angeles Dodgers RP

Fantasy rank over the last seven days: 517

Season-long fantasy rank: 368

After a poor second half in 2021, Craig Kimbrel looked like an easy bounce-back candidate after being acquired by the Los Angeles Dodgers just before the MLB regular season. The Dodgers seemingly improve every pitcher they acquire and Kimbrel had little to no competition for the closer role on one of the best teams in baseball. It was a match made in heaven.

Things haven't played out that way in 2022. Kimbrel has a 4.71 ERA in 22 appearances. He's been particularly bad lately, posting a 7.00 ERA over his last nine appearances.

Thankfully for Kimbrel's fantasy managers, better things are on the horizon. Over that same horrible stretch, he has a 2.24 FIP and .500 BABIP, suggesting he's been unlucky.

Despite his poor ERA, Kimbrel is doing some encouraging things in his first year with the Dodgers. His ground-ball rate is way up, which has led to an extremely low 5.6 percent home run per fly-ball rate. His strikeout rate is down, though still high enough to suggest Kimbrel is still a good pitcher.

There are still some reasons for worry, though. Kimbrel's walk rate is up and that's put him in some bad situations. His fastball, in particular, has been awful. Batters are hitting .341 against it. Kimbrel hasn't lost much velocity with the pitch, so he's either putting himself in fastball counts and getting knocked around or he's dealing with a mechanical or tipping issue.

When batters have reached against Kimbrel, they are coming in to score far more often than usual. Kimbrel's left-on-base rate is a low 64.4 percent. His career average is 82.3 percent, suggesting things will improve in that area.

It's been a rocky ride, especially lately, but there's enough to suggest there will be better days ahead for Kimbrel.