Waiver Wire Guidelines: Are These “Hot” Additions Really Worth The Risk?

by Eric Stashin (aka The Rotoprofessor)

It’s easy to get excited about the shiny new toy on the waiver wire, especially when they show a little bit of upside.  Are they really worth the addition, though?  Let’s take a look at three of the most added players recently and try to determine if they are worth it:


Marco Gonzales – Seattle Mariners
A former first round pick of the St. Louis Cardinals, his 5.02 ERA and 1.40 WHIP scream of a pitcher not worth owning.  However, when you look at the key statistics things start to look a lot more optimistic:

  • Strikeouts – 9.73 K/9
  • Control – 1.57 BB/9
  • Groundballs – 46.4%t

Over his minor league career he owns a 7.9 K/9 and 2.3 BB/9, including a 2.5 BB/9 at Triple-A, so the biggest question is if he’s going to be able to maintain his gaudy strikeout rate (his control may regress, but it should remain solid).  There has been a change in his approach, as he’s working in a cutter (15.04%).  With a 12.16% Whiff% on the pitch an improvement is justified, but an overall 8.9% SwStr% doesn’t elicit this type of strikeout rate.

Gonzales has also been hit extremely hard over his 28.2 IP, to the tune of a 29.8% line drive rate.  Obviously a .390 BABIP and 67.9% strand rate scream of poor luck, but it’s hard to imagine tremendous metrics.  Couple that with the regression expected in both strikeouts and control and what are we getting excited about?

Fantasy Waiver Wire Guidelines:

  • 10 Team League – Pass
  • 12 Team League – Pass
  • 14+ Team League – Potentially streamable
  • AL-Only League – Worth adding
  • Keeper/Dynasty – Potentially streamable


Junior Guerra – Milwaukee Brewers
There was a time that Guerra was viewed as a high upside starter, but injury and inability cost him in 2017 (5.12 ERA over 70.1 IP) and he ultimately spent a lot of time working out of the bullpen (14 starts in 21 appearances).  He’s back to starting in ’18 and pitching lights out, with a 0.82 ERA over 22.0 IP, but does that make him a strong buy or a player who clearly faces impending disaster?

Showing strikeouts (8.59 K/9) and control (3.27 BB/9), it would seem like he’s a starter we’d be all in on.  However that’s not reality.

Despite a similar strikeout rate, his SwStr% of 8.5% is well off his career mark (10.6%).  He also is carrying a career worst O-Swing% (24.5%), so why would we expect him to be able to maintain the mark?

After getting burnt by the long ball in ’17 (2.30 HR/9), Guerra has not yet allowed a home run in ’18.  His fly ball rate is down (43.7% to 39.6%), but does that justify 0 HR allowed?  Throw in an obvious regression in luck on the horizon (.232 BABIP, 87.5% strand rate) and a few blowups will be coming quickly.  Even as a streaming option, the risk outweighs the potential reward.

Fantasy Waiver Wire Guidelines:

  • 10 Team League – Pass
  • 12 Team League – Pass
  • 14+ Team League – Too risky to stream
  • NL-Only League – Too risky to stream
  • Keeper/Dynasty – Too risky to stream


Caleb Smith – Miami Marlins
Over six starts for the Marlins Smith has been piling up the strikeouts, with a 12.87 K/9.  That’s the type of number that’s going to grab your attention, and an overall 13.5% O-Swing% courtesy of a pair of swing and miss pitches (Whiff% of 21.05% on his changeup and 20.00% on his slider) support the performance.

Of course he’s never shown this type of upside before (8.9 K/9 over 102.1 IP at Triple-A), while he’s also struggled with his control (5.02 BB/9) and appears to be prone to home runs (1.26 HR/9, courtesy of a 28.1% groundball rate).  The control is a bit skewed, with 11 BB coming across two starts (and those starts spanned a total of 5.1 IP), but mix in a little big of luck (.267 BABIP despite a 21.9% line drive rate) and the fact that he pitches for the Marlins, making wins hard to come by, and nothing appears to be headed in the right direction…

Maybe he does maintain the strikeouts…  He should cut down on the walks (3.2 BB/9 in the minors)…  It’s still not enough, especially with the potential for home runs looming.  Maybe he’s worth streaming at home, but the matchup would have to be the right one.

Fantasy Waiver Wire Guidelines:

  • 10 Team League – Pass
  • 12 Team League – Streaming option at home
  • 14+ Team League – Streaming option at home
  • NL-Only League – Worth risk
  • Keeper/Dynasty – Streaming option at home

Sources – Fangraphs, Brooks Baseball, Baseball Reference

Missed our Top 100 prospect rankings?  Make sure to check it out by clicking here.  


  1. Mike Honcho says:

    What about Mahle, Wheeler, or Ty Anderson compared to the above?

    • Rotoprofessor says:

      Anderson is the most favorable. I probably prefer Wheeler/Mahle over them as well, though not by much

  2. Great analysis on tough pitches to decipher. I like C. Smith in a 14+ league and would start him depending on the match up. I have a chance to pickup Chris Stanton off waivers. Who would you recommend to drop A. Triggs or M. Boyd?

Leave a Reply

Your email address will not be published. Required fields are marked *