Last week's five biggest fantasy surprises: Have the Rays found their next Ben Zobrist?

When should a fantasy manager buy into a skill change? It's a complicated question that could have a massive impact on your fantasy league.

In the case of a young, promising prospect taking a step forward, like an Andrew Vaughn, fantasy managers hop on board early. Vaughn, and players like him, were always supposed to be good, so fantasy managers are willing to believe in a skills change relatively early.

But what about when that same phenomenon occurs with a player who has experienced multiple years of middling production? Fantasy managers are rightfully skeptical and tend to wait out those situations.

That presents a buying opportunity for those willing to do the extra research. If you're an early advocate of a previously mediocre player finding the next level, you might just end up with the next Ben Zobrist on your fantasy roster. Speaking of which ...

Ranks are based on standard Yahoo fantasy leagues

Isaac Paredes, Tampa Bay Rays 2B,3B

Fantasy rank over the last seven days: 1

Season-long fantasy rank: 528

The Rays already lived the Zobrist experience, and it's possible they have done it again.

Isaac Paredes is hitting .255/.315/.612 since being called up to the majors. He has an incredible 10 home runs in 34 games.

There are plenty of reasons to doubt Paredes' performance. Prior to 2022, Paredes had a .215/.290/.302 slash line, and only 2 home runs, in the majors. His performance in the minors was better, but Paredes wasn't thought of as a big-name prospect.

With that said, Paredes did show some talent. He made Baseball America's top-100 prospect list twice. He was listed at 94 in 2019 and 100 in 2020. Despite already spending two different seasons in the majors, he is only 23, an age where it's easier to buy his breakout.

Keeping in mind that it is only 34 games, the numbers show some promising signs. Paredes has upped his barrel rate and hard-hit rate, which could explain his sudden power jump. It also helps that his max exit velocity is 110.4 mph, which sits in the 70th percentile. Last season, Paredes' max exit velocity ranked in the 42nd percentile, a sign the Rays have unlocked the power potential in his bat.

Paredes is helping aid those power numbers himself with an extreme pull approach this season. Over 50 percent of his batted balls are being pulled and his fly ball percentage is up nearly 6 percent.

All of this is extremely promising. Paredes looks like a different player after joining the Rays in the offseason. Some regression is inevitable, as he's not going to maintain a .612 slugging percentage all season, but if you need help at second or third and are willing to make a speculative add, Paredes is already showing massive upside.

Cristian Javier, Houston Astros SP

Fantasy rank over the last seven days: 8

Season-long fantasy rank: 79

After throwing seven no-hit innings against the juggernaut New York Yankees, Cristian Javier deserves more attention. Following that performance, Javier now has a 2.73 ERA over 62 2/3 innings this season.

Is his breakout sustainable?

Javier has always shown plenty of ability but needed a steady opportunity. Now that he has one, this performance shouldn't come as a massive surprise.

With that said, Javier has actually cut down on one of his biggest weaknesses this season. His walk rate is down from 12.5 percent to 9.4 percent. He could still stand to improve in that area, but that's a positive sign nonetheless.

He's also experienced a lot of success with his fastball. Batters are hitting .168 against the pitch in 2022. It has slightly more vertical movement and Javier is using it to pound the zone up and in against righties. When they've made contact, batters are putting Javier's fastball in the air but not hitting it hard enough to do major damage.

There is one area of concern with Javier's breakout, however. He's turned into an extreme flyball pitcher this season. His 23.9 ground ball percentage would rank as the lowest among starters if Javier qualified for the ERA title.

Despite that, Javier's home run per fly ball rate is 4.8 percent, the lowest of his career by a wide margin. While it's true Javier is limiting hard contact, it's still a dangerous mix. Eventually, some of those fly balls are going to turn into home runs, which will elevate Javier's ERA.

Even with that, Javier still has plenty of value. Now firmly entrenched in the Astros' rotation, Javier should continue to be a viable fantasy starter. There should be some concern about an innings limit down the road, but he'll be an above-average fantasy starter as long as he's in the rotation.

Austin Riley, Atlanta Braves 3B

Fantasy rank over the last seven days: 591

Season-long fantasy rank: 55

Austin Riley hasn't fully lived up to last season's breakout, though that has not impacted his fantasy value much. Riley still ranks 55th among all players even though he's lost .050 off his batting average in 2022.

Last week was particularly bad, as Riley went just 3-for-15 with zero home runs. Slumps happen to every player and Riley managers should not be concerned long-term.

So why focus on him here? Because there's potential for him to be even better than the 55th overall player moving forward.

Riley has somehow become even more of a monster at the plate. His average exit velocity is 93.4 mph, which puts him in the 97th percentile. His barrel rate of 15.7 percent is even better than last year and puts him in the 93rd percentile. His hard-hit rate is up and he's putting the ball in the air more often. That should lead to some immense home run numbers, but you knew that when you drafted him.

What about the batting average? Riley's .307 figure from last year was propped up by a .368 BABIP. It would be tough for Riley to maintain that, though hitting the ball hard could offset some of that loss. Some of the batting average struggles are legitimate, though. Riley is chasing pitches at a slightly higher rate and striking out more often.

But there's still a chance he improves on those figures. Riley's performance against fastballs has taken a massive dip in 2022. After hitting .291 with a .508 slugging percentage against fastballs in 2021, Riley has a .230 average and .454 slugging on fastballs in 2022. Riley is actually hitting fastballs even harder in 2022, so it's tough to imagine those struggles will continue.

If you drafted Riley, you're probably satisfied with his performance. While he hasn't been as good as last season by the numbers, there's evidence that he's actually been a better hitter this year. It's possible he takes another step forward in the second half and finishes even higher than he did last year, when he was the 40th-ranked fantasy player in standard Yahoo leagues.

Lance Lynn, Chicago White Sox SP

Fantasy rank over the last seven days: 547

Season-long fantasy rank: 704

Fantasy managers who waited this long on Lance Lynn have to be disappointed after his first three starts. Lynn is carrying a 6.19 ERA over those first 18 innings — not what you want.

On the surface, Lynn looks like generally the same pitcher. His strikeout rate remains solid and his walk rate is elite. He's experienced some bad luck with his .354 BABIP, 20 percent home run per fly ball rate and 52.9 percent left-on-base percentage. All three figures are so outside Lynn's norm that they should all improve as the season goes on.

It's also worth digging through his game logs to see just how Lynn has struggled. His first time out was bad. Lynn gave up 10 hits against the Detroit Tigers and was unable to go deep into the game. His two other outings have been solid — until his final inning. Lynn gave up one earned run over five innings against a tough Toronto Blue Jays offense before unraveling in the sixth. He had a similar experience against the Baltimore Orioles, giving up two runs over six innings before things fell apart in the seventh.

Lynn bears some responsibility there, but it's also on White Sox manager Tony La Russa to recognize when Lynn needs to be removed from games. Lynn threw 99 pitches against the Blue Jays and 109 against the Orioles in his second and third starts back from the injured list. Had La Russa exercised more caution, Lynn managers would probably feel much better about the start of his season.

La Russa remains Lynn's real-life manager for now, which is troubling. Ideally, Lynn won't experience as much fatigue later in starts as he makes a few more appearances. He's shown enough to suggest he'll still be an above-average fantasy starter soon. Fantasy managers shouldn't panic after a disappointing start to the year.

Jon Berti, Miami Marlins 2B,3B,OF

Fantasy rank over the last seven days: 17

Season-long fantasy rank: 121

If your league values steals, Jon Berti should already be rostered. He leads the majors with 22 stolen bases, has been caught just twice and owns one of the best sprint speeds in baseball. He seemingly gets the green light every time he's on base, meaning he'll continue to post gaudy stolen base totals.

With the stolen bases guaranteed, the biggest question is whether Berti can keep up this offensive production. Berti is hitting .297/.389/.421 on the season. All three of those figures would represent a new career-high for Berti (if you take out his four-game sample from 2018).

Maintaining those numbers is going to be difficult. Berti is running a .394 BABIP, which is likely to regress. His speed can help in that area, as fast players can leg out more hits when they put the ball in play, but a BABIP near .400 is extreme.

Berti also hasn't really altered his game much. He's not known for hitting the ball hard and that hasn't changed. His barrel rate is higher, though that isn't saying much compared to what Berti has done in the past. His launch angle is also higher, though not extreme. It should, however, allow Berti to leg out more extra-base hits, so perhaps his slugging percentage gains will stick.

Overall, there's very little to suggest Berti is in the midst of an offensive breakout. He deserves to be rostered based on his ability to steal bases, but there may come a time where fantasy managers want him on the bench if they already have steals wrapped up — because once regression hits, Berti won't be able to provide much else.