Fantasy Baseball 2021: How to determine which pitchers to add off the waiver wire

Fred Zinkie
·Yahoo Fantasy Contributor
·4-min read

Last week I discussed my process for adding free-agent hitters.

If you thought that process was confusing just wait until we dive in on pitchers.

With hurlers, there is constantly a sample-size issue. Luck sometimes plays a major factor in the ERA and WHIP for relievers who throw just one inning per appearance. And with starters pitching just once every 5-6 days, we need several weeks before seeing a consistent trend. But we can’t wait weeks to add interesting pitchers, or else the rest of our leaguemates will get all the good ones. We need to be aggressive but measured at the same time, which is a challenging mission.

Here are my key factors when evaluating a pitcher.


Although talent is a major factor that we will soon discuss, in mixed leagues I generally don’t have room to stash pitchers who cannot be used right away. For me to have major interest in a free-agent hurler, he needs to be in the starting rotation or handling ninth-inning duties. Setup men can be valued parts of my squad, but they are not the players who I am primarily chasing.

K:BB ratio

For all of the advanced pitching data that is now available, the old-fashioned measurement of strikeouts and walks is still incredibly valuable. Pitchers who can’t consistently record punchouts are prone to the whims of batted-ball luck. And those who issue too many walks are going to eventually get burned by giving opponents free chances to score. The K:BB ratio leaderboard is typically full of aces, and I would prefer a 3:1 ratio for my waiver wire additions.

Velocity or pitch changes

This data requires a little more research, but checking a pitcher’s recent velocity and pitch mix can sometimes expose breakout candidates. An example on the highest end is Jacob deGrom, who went from excellent to unbelievable by adding a couple of mph. Michael Fulmer is an example of a pitcher I am monitoring right now after noticing that his velocity is up this year.

Detroit Tigers pitcher Michael Fulmer
Is Michael Fulmer poised to have a breakout season? (AP Photo/Paul Sancya)

Batted-ball data

I want to know what type of contact a pitcher is giving up and how much of their recent success or failure has been related to luck. In terms of contact, I prefer pitchers who induce plenty of grounders and limit hard contact. And I want to check a pitcher’s BABIP and HR/FB percentage to find out if he has been lucky or unlucky in giving up hits and home runs. For example, my interest in Austin Gomber cools when I notice his .160 BABIP.

Upcoming schedule

This category means little for relievers but a whole lot for starters. Before adding a starter, I like to know his next 2-3 opponents. Sometimes rainouts or rotation shuffles alter future rotation plans, but I want to give myself my best chance for success by grabbing pitchers who should have reasonable matchups in their upcoming outings.

Supporting cast

Although pitcher talent is the driving force, finding those who are in advantageous situations is always beneficial. When assessing supporting cast, I’m going to look at three areas. First, I want to know that my hurler is backed by a lineup that has the potential to score plenty of runs. Second, I’m looking for starters who are backed by solid bullpens, and I’m targeting potential closers who are on successful teams. Finally, I prefer a pitcher (especially a starter) who works in front of a respectable defensive group.

Home park

As with supporting cast, home park is more of a tiebreaker than a primary factor. Still, I prefer to grab hurlers who call home to a neutral venue at the very least. On the extreme end, there is little upside to adding a Rockies starter who will stay on my bench for all of his home starts. And pitchers on most AL East teams will be battling against their own home park and their most common road venues.


This piece of criteria matters much more in some cases than others. At times I am looking for Mr. Right and other times I’m looking for Mr. Right Now. This piece is advice more for those in leagues that use FAAB or waiver priority. To make a major investment, I need to know that the player can stay in his current role by performing well in the coming weeks. Players who are only temporarily working in the rotation or closer’s role are worth only minimal attention.