Danny Duffy, 6'3", 205 lbs, left-handed

Drafted in the 3rd round in 2007.

THE MINORS

2007: Went 2-3 with a 1.45 ERA and 1.10 WHIP along with 63 strikeouts over 37.1 innings at Rookie Ball as an 18 year old. 

2008: Duffy went 8-4 with a 2.20 ERA, 0.99 WHIP and 102 strikeouts over 81.2 innings at Single-A ball.

2009: At High-A Duffy was 9-3 with a 2.98 ERA, 1.18 WHIP and 125 Ks in 126.2 innings. 

2010: Duffy retired at 21. He changed his mind and returned in June. Saw time at three levels (Rookie, High-A, Double-A). Danny went 5-3 with a 2.74 ERA, 1.11 WHIP and 69 Ks in 62.1 innings. 

2011: Entered the years as the 68th ranked prospect in baseball according to Baseball America and 67th according to Baseball Prospectus. Made eight outings covering 42 innings. He went 5-2 with a 2.95 ERA and 1.19 WHIP. 

2012: Didn't throw a pitch as he was recovering from Tommy John surgery.

2013: Made 16 outings at Double and Triple-A. Duffy had a 4.04 ERA, 1.39 WHIP and 87 Ks in 69 innings. 

2014: One start covering six innings.  

TOTALS: 31-16, 2.88 ERA, 1.15 WHIP, 10.5 K/9, 3.53 K/BB ratio over 425 innings. 

THE MAJORS

2011: As a rookie he went 4-8 with a 5.64 ERA and 1.61 WHIP over 195.1 innings. Struck out 7.43 batters per nine with a humorously hapless 1.71 K/BB ratio.

2012: Made six starts before injury his elbow which required Tommy John surgery. Went 2-2 with a 3.90 ERA, 1.59 WHIP and an atrocious 5.86 per nine walk rate. 

2013: Made five starts with a 1.85 ERA, 1.36 WHIP an a 1.85 ERA. Walked more than five batters per nine leading to a terrible 1.57 K/BB ratio.

2014: Everything came together. Made 25 starts (31 outings) leading to a 2.53 ERA and 1.11 WHIP. Only went 9-12 and saw his strikeout rate plummet to 6.81 per nine. 

THE SKILLS

The ERA and WHIP that Duffy posted last season simply weren't earned. Take a look.

3.83 FIP
4.42 xFIP 
4.31 SIERA
3.89 DIPS

Remember, Duffy posted a raw ERA of 2.53 - more than a run an a quarter below any of the four measures. Which number do you think is legit? The 4.11 average of the advanced measures or the 2.53 ERA? It's no logical to go with the ERA here. 

So why didn't Duffy "earn" his ratios?

Duffy was better than a K per inning arm in the minors. He hasn't been that guy in the majors other than a 27.2 inning stretch in 2012. From 2011-13 Duffy struck out an average of 7.84 batters per nine. Last season that mark dipped all the way to 6.81 per nine, a catastrophic fall (the league average was 7.73). He threw his changeup less than he had previously while upping his curveball usage. Nothing drastic, just a couple of percent with the pitch types, but the results simply were not there in the strikeout column. 

Duffy slashed his walk rate substantially after posting a 4.75 mark per nine his first three years. At the same time, the 3.19 mark he posted in 2014 was worse than the league average of 2.89. Duffy did walk 3.0 per nine in the minors so it's possible he can replicate his 2014 effort, but even if he does that he's still worse than the league average.

Last season the major leagues K/BB ratio was 2.67. Duffy posted a mark of 2.13. That's 20 percent below the league average. That's awful. It's also the first time in four years his mark was over 1.75. That's pathetic. For his career, covering 306.2 innings, Duffy owns a wretched 1.84 mark. 

A pitcher with a 6.81 K/9, 3.19 BB/9 and 2.13 K/BB ratio has no place on any of my teams. Not one. The only exception would be if that arm is a great ground ball inducer. Duffy doesn't fit that mold - at all. 

Duffy doesn't generate grounders. For his career his ground ball ratio is 36.0 percent. In 2014 that mark was 35.8 percent. The average big leaguer posts a mark of about 45 percent. Another example of Duffy being below the league average. Shocker.

Duffy allows too many fly balls. The big league average is about 35 percent. In 2014 Duffy's mark was 46 percent. Yet again Duffy is well below average in yet another measure.

And here's the real issue. It's extremely difficult to envision a scenario in which Duffy allows those hit rates and yet against posts strong ratios. Let me count the ways.

(1) Duffy is worse than league average in his ground ball and fly ball rates.

(2) Given all the fly balls he allowed last season a 0.72 HR/9 mark isn't sustainable. 

(3) The league average GB/FB ratio is about 1.20. For his career Duffy owns a mark of 0.83. It was 0.78 last year. 

(4) Duffy had a .239 BABIP in 2014. Not only was that more than .040 points below his career average and .060 points below the league average, it's also a rate that is nearly impossible for a starting pitcher to repeat - no matter the skill level of that arm - in back-to-back seasons. 

(5) Duffy had a 77.2 left on base percentage last season. That's a very high number. Among pitcher that threw at least 140-innings last season it was the 26th best mark in baseball. Even the elites of the game struggle to consistently hit that mark (even Clayton Kershaw is only at 78.3 percent for his career).

Finally, what about durability/workload concerns? Here are Duffy's yearly innings pitched marks (majors + minors).

2007: 37.1 innings
2008: 81.2 innings
2009: 126.2 innings
2010: 62.1 innings
2011: 147.1 innings
2012: 27.2 innings
2013: 93.1 innings
2014: 155.1 innings

As you can see Duffy has never thrown 160 innings in a season. Ever. How could that not concern you with a player who has been a professional since 2007? How can you lean on a guy that you cannot trust to pitch an entire season?

CONCLUSION

Duffy didn't truly earn the success he had last season. As detailed above, pretty much everything went right for Duffy leading to ratios that aren't likely to be repeated. Consequently  it's quite possible that Duffy will be wildly overdrafted in some leagues. Don't be one of those folks. Avoid the misery that you will reap if you opt to take Duffy as a staff ace or anything close to it.

10 team lg: No interest at all. Do not draft him.

12 team lg: Mild interest only. Nothing but a streaming option. 

15 team lg: Could take a chance in a league this deep if the cost isn't obnoxiously high. Still, he's likely best served as a spot starter and not someone you blindly role out there start after start.

AL-only: It's all about the benjamins  baby. If the cost is acceptable then go for it. In terms of that cost, Duffy isn't anything other than an SP 3/4 though - hopefully a #4. The loss of strikeouts, too many walks, and no history of sustained health makes him too expensive if you're thinking about those non-repeatable ratios.