Fantasy baseball waiver wire: Mets call up rookie Brandon Sproat who presents major Fantasy upside

The Mets have become one of the best pitching development organizations in baseball seemingly overnight, and they're promoting yet another big win for their playoff run, with Brandon Sproat set to make his major-league debut Sunday against the Reds. 

And boy, do they need it. Their rotation has been in slow-motion free-fall for the past few months. Which can't have been a surprise to the team's brass – they built the rotation largely out of cast-offs on short-term deals, and they did an excellent job wringing everything they could out of the likes of Sean Manaea and Frankie Montas. But with Manaea slumping, Montas out for the season, and Kodai Senga mulling a trip to the minors to try to figure out why things have gone so wrong for him, the only bright spots lately have been David Peterson and a couple of rookies: Nolan McLean and Jonah Tong. And now Sproat will look to give them three young, potential aces for the playoffs. 

It's been a wild ride for Sproat. The Mets drafted him twice after failing to sign him the first time, and he looked like one of the most exciting pitching prospects in baseball last summer, when he reached Triple-A with an ERA in the low-2.00s at his first two levels. But he was a disaster in seven late-season starts at Triple-A, and those struggles continued for the first few months of 2025, as he had a 5.95 ERA and a miserable 4.0% K-BB% through his first 15 starts. 

Blessed with high-end fastball velocity, Sproat's heater nonetheless has a bad shape and struggles with command, and the rest of the arsenal wasn't good enough to make up for it. Sproat was passed in the organization's pitching hierarchy by McLean and Tong, but he also started righting the ship himself in July, even as those guys were passing him.

There wasn't some dramatic shift in pitch usage – a few more four-seamers and fewer sinkers, more changeups and curveballs, fewer sliders and sweepers – but there was a huge change in effectiveness. Since July 1, Sproat has a 2.72 ERA with a 30% strikeout rate and 8.5% walk rate, and the whiff rates on the sweeper, changeup, and four-seamer improved dramatically. 

The fact that his pitch mix and velocity didn't change along with his improved performances is a little concerning against better competition – is he going to fall back on the bad habits and poor control that threatened to sink his prospect status? – and I do think Sproat is less exciting than either McLean or Tong were at the time of their promotions, let alone now. But that doesn't mean Sproat isn't interesting for Fantasy. 

He's got a legitimate starter's arsenal, has shown high-end potential, and seems to have figured out whatever went wrong for him for his first four months at Triple-A. He gets a decent landing spot against a Reds team that ranks seventh in strikeout rate while being middle of the pack offensively overall, and if he pitches well, there's every reason to expect he'll stick in the rotation alongside his fellow rookies. And there's at least a chance he ends up being a difference maker with the growth he's shown over the past couple of months. 

Sproat isn't a must-add pitcher in all Fantasy formats, but if you play in a league with free agent adds before his start, I think it's worth adding him before his start, just in case he looks like a potential difference maker. You don't want to miss out on that upside -- or have to fight everyone else for him -- if he shows it. 

Some more waiver-wire targets

Kyle Manzardo, 1B, Guardians (47%) – Manzardo can mash righties. His homer off Pete Fairbanks Thursday was his 20th of the season off a righty, and he's got an OPS near .800 against them for the season. But here's the thing about Manzardo: He might be able to hold his own against lefties, too. He has a .716 OPS against them this season, with a .353 expected wOBA, which is playable regardless of whether you take the low end or high end. His value has been held back by the Guardians' insistence that he is just a platoon bat, but they may be softening in that stance lately, as Manzardo has started three straight against lefties. This is one to keep an eye on down the stretch, because if the Guardians keep giving him those opportunities and he proves he can handle them, he could be an overlooked sleeper in drafts next season. And he could be a very valuable bat in September, too. 

Nick Yorke, 2B, Pirates () – Yorke's return to the majors went under the radar, but Scott White noted that he might have a chance to play his way into an everyday role as the Pirates second baseman earlier in the week, and he put in some work Thursday, going 1 for 3 with a double and a couple of RBI in a surprise win over the Dodgers. That's not enough for Yorke to be a must-add option in Fantasy or anything, but hopefully it's enough for the Pirates to give him some extended run down the stretch. Yorke is a former first-round pick and top-50 prospect who has had an up-and-down minor-league career, but he has at least performed better in the higher levels, including an .825 OPS in Triple-A. There's a little bit of pop and some speed here, and in deeper categories leagues, he could be worth a look.