Sneaky Fantasy Baseball Waiver Wire Pickups, Buys: Week 13 - Hot Pitchers To Sustain Success?

June 23, 2026

Andy looks at four sneaky fantasy baseball waiver wire pickups for starting pitchers in Week 13 (2026) on hot streaks, and sees if they can sustain their success.

Welcome, RotoBallers, to another edition of my Sneaky Start Pitcher Waiver Wire Column. As always, we will spotlight four starting pitchers who are widely available and determine if their recent hot surge can be sustainable.

In this week's edition, we will look at a resurgent arm in San Diego and Queens, among others.

Be sure to follow RotoBallerMLB on X for all of our league-winning content and me, @A_Smith_FS, for any questions! Additionally, be sure to use the discount code SMITH at checkout for 50% off any Premium Packages. Note: All advanced statistics referenced are updated as of Monday, June 22.

Walker Buehler, SP, San Diego Padres

25% Rostered (Yahoo)

Walker Buehler was once a fantasy ace of the Los Angeles Dodgers. Out in Los Angeles, Buehler became a high-end fantasy performer and was widely regarded as one of the best pitchers in the game during his "prime." From 2018 through 2021, Buehler led a strong 2.82 ERA with a 0.99 WHIP across 564 innings of work with the Dodgers.

However, Buehler would then take a step back the following season, logging a 4.75 ERA in 2024 before taking an even further step back in 2025, posting a 4.93 ERA and a 1.52 WHIP across 126 innings split between stints with the Phillies and Red Sox.

Entering 2026, Buehler was left for those in deeper NL-only leagues, as it appeared the 31-year-old was nothing more than a volume option to fill innings in the pecking order of formats. However, Buehler has been able to rekindle his previous success in San Diego, which has put him firmly back on the fantasy radar.

Since June 1, Buehler has been quietly dominant, logging 21 innings with a 1.71 ERA and a 1.33 WHIP. Prior to this stretch, Buehler held a 4.88 ERA and a 43:18 K:BB over his first 51 2/3 innings of work. Can managers trust this recent stretch of performances?

When looking at his pitch usage over the course of the season, managers cannot spot many major changes in June. This summer, Buehler has leaned on a three-pitch fastball mix (sinker, cutter, and four-seamer) while using his slider as his primary breaking ball. As shown below, his slider usage has climbed in June, which has pushed his knuckle curve to a much lower usage rate.

This change is worth noting as his slider has been very impressive in June. So far, this pitch has posted an impressive 39.3% whiff rate with a low .143 xwOBA. Buehler may even enjoy further positive regression with this pitch, as suggested by the surface-level .269 wOBA.

While on the season, his three-pitch fastball combination carries the most impressive metric, as it has begun to improve in June. Both his four-seamer and cutter have posted the lowest xwOBA by month in June, with his cutter carrying an impressive .218 xwOBA. By mixing in his slider, he has been showing far more promise with his fastball, especially his cutter.

Seeing that he has been able to rely on his cutter as his true No. 1 pitch (over his four-seamer) is also a very positive sign for his rest-of-season outlook.

When examining his overall profile, managers may be concerned about his rough 4.38 xERA (39th percentile) and .271 xBA (16th percentile). However, these marks have been greatly affected by his struggles earlier in the season. Additionally, his modest 21.1% K% has continued to climb thanks to his added slider.

Over the first two months, he posted a pedestrian 7.5 K/9, but this number jumped massively in June to 9.4 K/9. His 47.9% ground-ball rate should also continue to help him limit damage, given that he does still allow low contact.

While Buehler will not return to his Cy-Young caliber of play, he is looking like a prime return candidate. Pitching in a "pitcher's park" and throwing his arm has opened the door for him to be a viable pitcher in 12-team leagues as an SP4 with upside.

Joey Cantillo, SP, Cleveland Guardians

25% Rostered

Joey Cantillo has flashed high upside at times, but has yet to sustain it over a lengthy period of time. During the 2025 season, Cantillo emerged as a late-season waiver wire gem, posting a 2.48 ERA with a 1.12 WHIP over his final 54 1/3 innings. But this came as a surprise as he posted a much higher 4.17 ERA over his first 41 innings of the campaign.

As a result, he carried some intrigue for fantasy managers entering 2026 but ensured some growing plans early on. Over his first 34 1/3 innings of work, Cantillo carried a 1.40 WHIP as he walked 4.2 hitters per nine innings but was also able to mitigate most of the damage, as shown in his 3.67 ERA. While he went on to post a 5.51 ERA over his next 32 2/3 innings, he has recently begun to turn the corner.

In his last two outings, the young southpaw has logged 13 innings to the tune of a 1.38 ERA, 0.85 WHIP, and a near-perfect 13:1 K:BB. Not only is his improving command worth noting, but so is his strikeout production.

While Buehler made only subtle changes, Cantillo is the opposite. In June, the lefty has leaned much higher on his curveball, especially in his most recent outing.

In June, his new primary option has been elite. This curveball has generated an eye-catching 37.3% whiff rate with a .219 xwOBA. Per Tim Stebbins of MLB.com, in his most recent start on June 20 (against the Astros), he deployed this pitch 44 times and limited Houston hitters to a rough 2-for-22 line.

While his four-seamer remains a weakness in his arsenal (.453 xwOBA in June), his changeup has posted a dominant .168 xwOBA in June, compared to the high .338 xwOBA in May. By mixing in his curveball more often, he has not only maintained a +30.0% whiff rate but has also limited it to dangerous contact.

Like Buehler, Cantillo's overall 4.20 xERA does not instill much confidence, but he has begun to make the necessary adjustments. However, the young lefty will need to master a four-seamer to truly develop into a consistent fantasy arm. His changeup and newly found curveball have put him on the SP5 radar and a worthy look in favorable matchups.

Sean Manaea, SP/RP, New York Mets

15% Rostered

Manaea put together a productive season in Queens when he tossed 181 2/3 innings to the tune of a 3.47 ERA and a strong 1.08 WHIP back in 2024. During this campaign, Manaea emerged as their "ace," striking out 184 while walking 63. However, injuries prevented him from mounting any of this momentum during the 2025 season, as he logged only 60 2/3 innings with the Mets.

During this stretch, Manaea held a much higher 5.64 ERA with a modest 1.22 WHIP. Entering the 2026 season, Manaea's role was not even guaranteed as the team would bring in Freddy Peralta in the offseason and have the emerging Nolan McLean serving as a high-end No. 2 option.

However, with much of the rotation struggling or dealing with injuries, Manaea has been "promoted" from his long-relief role and reclaimed a spot in the starting rotation. Over his first 22 innings of work, Manaea posted a 6.55 ERA and was trending towards putting together another disappointing campaign as he did the year prior.

Since then, the southpaw has found his footing, which has pushed him back into a starring role. Over his next 21 frames, the lefty would post a 3.43 ERA with a 1.24 WHIP. Over his last two games, Manaea was deployed in a starting role and looked even more comfortable, logging 11 1/3 innings with a 3.18 ERA and an 11:1 K:BB.

As shown in the visual below, Manaea has not tweaked his pitch mix much this season, aside from a few minor changes. In June, Manaea has leaned on his sinker less, and slightly opted to pitch his cutter while keeping his four-seamer and sweeper as his clear No. 1 and No. 2 options.

When looking at the underlying metrics, Manaea is beginning to show some positive regression in his "expected" stats, which had been hinting at it. While his four-seamer is nearly in lockstep with the .332 xwOBA under the hood (.333 wOBA), his sinker has generated a strong .264 xwOBA (.307 wOBA), and his sinker a .325 xwOBA (.374 wOBA).

Additionally, his sweeper (which is expected to be thrown more in June) has posted a strong 35.6% whiff rate this summer, which could be the catalyst for improved strikeout totals as the summer progresses.

Early in the season, the southpaw was due for some positive regression, and it finally showed up in the box score. His current 4.06 xwOBA is still nearly a point lower than a 4.64 ERA on the surface, and his .246 xBA puts him just below the average marks. Managers should also begin to see more strikeouts in his box score, as his 32.4% chase rate is well above average, but his 23.6% K% is just above average.

The increased usage of his sweeper should keep Manaea on the high-end streaming radar and viable SP4/5 in deeper leagues.

Javier Assad, SP/RP, Chicago Cubs

15% Rostered

Rounding out this week's column might be the most surprising name that we have covered this season. Javier Assad has found success with the Cubs throughout his career, bouncing between the bullpen and the starting rotation. However, the 28-year-old is enjoying the most dominant stretch of his career and has been a top-12 option at the position for nearly the past two weeks.

Additionally, with injuries to the Cubs' rotation, Assad has been bumped from his long-relief role to the starting rotation, similar to Manaea.

Over the first 19 innings of the campaign, the right-hander posted a rough 7.58 ERA with a 1.47 WHIP. Even though his ratios were greatly inflated by a six-run showing and a season-worst nine-run showing, he was not rostered in any standard leagues. However, since the start of May, Assad has held a ridiculous 1.08 ERA and a 0.64 WHIP over 25 innings.

During this dominant stretch, the right-hander has struck out just 14 hitters but only walked three. In these six outings, only his most recent two have come out of the starting rotation, which saw him post a 1.54 ERA over 11 2/3 innings.

Is this the start of a Year 5 post-hype breakout?

The 28-year-old is not a flamethrower by any stretch and is a weak option for those looking for strikeouts on the waiver wire. On the season, he has generated a 14.5% K%, which puts him in the fifth percentile of all qualified pitchers. However, his elite 5.2% BB% rate has offset this quite well, making him a top target for ratio assistance.

Since his dominant stretch started on May 1, Assad has made a handful of tweaks to his repertoire, but the majority of his kitchen-sink approach has remained intact. As shown below, Assad leans on his sinker (but has begun to rely on it less in June), while mixing in his four-seamer and cutter at least 16.0% of the time and adding a changeup, curveball, and sweeper at least 7.0% of the time.

His sinker has been the driving force behind his success, posting a .171 xwOBA in June, which contains a decline relative to his previous month's production. The one pitch to watch is his sweeper. He has begun to rely on it the most in June (first time his double-digit usage in a given month) and has generated an elite .043 xwOBA this month with a 33.3% whiff rate.

This season, it holds a dominant 41.2% whiff rate and a sparkling .084 xwOBA. While this number will climb as the usage increases, it is shaping up to be the best pitch in his deep arsenal.

If Assad can continue to lean on his sweep as a true breaking ball option, his K% will continue to climb, even if it remains firmly below the average mark. While regression is expected, Assad has a deep arsenal that keeps hitters off balance. His high ground-ball rate (46.7%) plays well in the elite Chicago infield, which is occupied by some of the game's top defenders, and his limited flyballs are handled well by the gold gloves in the outfield, Ian Happ and Pete Crow-Armstrong.

The 4.03 xERA suggests regression, but even if his ERA climbs to the mid-3.00s, he will remain valuable in fantasy, especially when looking at WHIP. Those needing a ratio stabilizer who should see ample win opportunities should look to target him this week.

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