Danny Duffy and Jake Arrieta are both pitchers who have burst onto the fantasy scene this year despite very low expectations coming into the season. Their ownership rates in fantasy leagues were practically zero on Opening Day but that changed gradually as the season wore on and both are now owned in nearly all competitive leagues of 12 or more teams. In 5×5 roto leagues Arrieta ranks as the 23rd best starting pitcher in 2014 while Duffy comes in one slot behind at 24th. That is better than Stephen Strasburg, Yu Darvish, Jeff Samardzija, Sonny Gray, Jeff Weaver, James Shields and many other good pitchers.

If you compare their statistics you can see a lot of similarities:

Both look like excellent young fantasy starters. Both have stellar ERA and WHIP scores. Both have well above average fastball velocity. Since they look so much alike it seems this smackdown could end in a tie. We are going to have to look much deeper into their peripherals to figure out which of these guys is better than the other:

Now we begin to see some big differences. Despite the fact their fantasy numbers and rankings are almost exactly the same, now we can clearly see that one of these guys has pitched much better than the other, and furthermore one of these two is much more likely to put up elite fantasy stats next year. The clear cut winner in this battle is Jake Arrieta, who has huge leads over Duffy in all of the key stats above. These are the most important metrics for evaluating the performance of pitchers. These peripherals portray a stark contrast between a pitcher who is having a dominant season (Arrieta) and a pretender who is skating on thin ice (Duffy).

Danny Duffy — Kansas City Royals

Duffy’s 2.42 ERA is exactly two full runs better than his xFIP, and that is not a good thing because xFIP is much better at predicting the future than ERA. An ERA over 4.00 in today’s offensive environment would be a nightmare for your fantasy team. He has been very BABIP lucky with his .232 mark. His strand rate also indicates good fortune. Duffy doesn’t strike out enough batters, especially when compared to his walk rate. His 2.16 K/BB rate is indicative of a pitcher who is going to struggle. Duffy’s 93.3 MPH fastball is nice but he relies on it too heavily, largely because he doesn’t really have the depth of repertoire that one would hope for from a starting pitcher. He has a curveball that he throws 22% of the time and a changeup he only uses for 9% of his pitches. He is a  flyball pitcher who allows a lot of contact, but surprisingly his home run rate has been good, although I would expect that to rise as time goes by. Duffy is 25 years old but he has been in the big leagues since 2011.  He needs to learn another pitch to prevent batters from sitting on his fastball. Now would be a good time to trade Duffy as his value is at its peak. I would not risk using him in your fantasy playoffs if you have other decent options. Verdict: Fantasy Mirage. Trade him this winter.

Jake Arrieta — Chicago Cubs

Arrieta’s excellent ERA is fully supported by his underlying peripheral stats. His FIP, xFIP and SIERA all show that his 2.81 ERA is no fluke. Arrieta’s strikeout rate and walk rate are both 50% better than Duffy’s, so it is no surprise that Arrieta’s key K%-BB% metric is almost double that of Duffy. Pitchers just don’t succeed for any length of time with strikeout and walk rates as pedestrian as Duffy’s, but Arrieta’s rates are very good and portend continued success. Arrieta utilizes a four pitch mix that is basically the same as Duffy’s but adds in a good cutter that not only gets hitters out but also makes his other pitches more effective as well. Arrieta throws his fastball 50% less often than Duffy throws his, making it much harder for hitters to sit on it. Arrieta is 3 years older than Duffy. Despite this being the first year of sustained success for Arrieta he has shown signs of an impending breakout in prior years, especially in 2012 when he posted a 3.66 SIERA and 3.65 xFIP despite an horrific 6.20 ERA. In that 2012 season his good peripheral performance was masked by atrocious luck stats including a .320 BABIP and woeful 57.3% strand rate. The cutter is a new pitch that Arrieta has incorporated into his arsenal this year and it has worked like magic. He is a much better pitcher now than he was with the Orioles and his success is going to continue. Verdict: The Real Deal. Will continue to be a #2 fantasy pitcher moving forward and makes a good trade target.

Arrieta wins the smackdown! Does anybody disagree? Are there any factors I should have considered? Who should square off for next week’s epic smackdown? Leave your thoughts in the comments below.

If you have Duffy on any of your teams you should try to trade him for Arrieta. If you can trade Duffy for any top 75 starting pitcher I would do it.

If you missed last week’s column you can check it out here: Prospect Perspective: Nolan Arenado and Nick Castellanos are Still Elite Prospects.

Nick Doran writes all kinds of cool stuff about the game’s ultimate flamethrowers at Blazing Fastball and will answer your baseball questions on Twitter @BlazingFastba11.