Let me begin (and probably end) by saying that my argument here is in no way an indictment of Todd Helton and that I don't believe batting eighth in the lineup, especially one this good and this deep, is a slight or means that you are less valuable than all the hitters in front of you.
This isn't little league. At this level, batting eighth requires a unique skillset that, in many ways, can be more of a key to the teams offensive success than the few spots that precede it. Because, in the National League, the ninth spot usually represents as close as you can get to an automatic out as you can get, the eight-hole becomes integral to a teams ability to provide consistent offense. Being able to turn the lineup over while remaining a threat to score but resisting the temptation to try and do too much with bad pitches (thereby chasing your way into outs) is a tricky equilibrium to reach and one that Todd Helton has had the skillset for his entire career.
I absolutely love RIRFs new "Drag Factor" statistic and think it provides some great insight for this conversation. Check out his video for a full explanation, but know for our purposes here that the basic premise is that the best offenses have both firepower (Cargo, Tulo, etc.) and limit the number of easy outs (drag) throughout the entire lineup. The less drag the lineup has, the more opportunities the big-boppers will get to hit, and theoretically, to hit with runners on base. Putting Todd Helton eighth in the lineup allows him to capitalize on his excellent eye and plate discipline skills, while lessening the burden of needing to be able to consistently drive the ball.
According to Fangraphs, Todd Helton is walking less than he ever has in his career by a lot. He is at 8.6 percent down from a career 14.3 percent and 13.8 percent last season. He is also swinging at a much higher rate across the board. He is swinging at 46.1 percent of the pitches he has seen this year, 64.4 percent of the strikes and 25.5 percent of the balls, all career high numbers by about five percentage points. But even while walking less and swinging more, Helton's contact rate remains very Helton-y, which is to say right about at his career averages, just without much of the power.
In fact, Helton is actually making slightly more contact on pitches outside the zone than pitches thrown for strikes. This suggests to me that he clearly still has the ability to cover tough pitches and work counts, but feels the need to be more aggressive especially during RBI opportunities. Also, because Helton's overall numbers aren't what they used to be, pitchers feel more confident going after him in deeper counts. Being careful with Todd Helton to get to Josh Rutledge or Nolan Arenado doesn't really make sense right now but I believe pitchers would be less likely to challenge Todd if they see their counterpart in the on-deck circle. Because he is so good at it, this would inevitably lead to more walks and less drag on the lineup.
When you put a player like, say Josh Rutledge, in the eighth spot, you are putting an aggressive hitter in a position where he needs to take a more patient approach, not letting him do what he does best. Todd Helton is the best player on the team in terms of pitch recognition and situational analysis. Hitting Helton eighth gives the Rockies a better chance to avoid outs from that spot while letting their more aggressive hitters be aggressive.
Helton has a Drag Factor of .44, which isn't too bad (again, see RIRFs charts in the video segment), but could be better if not for the outs he is making that used to be walks. Helton could go from a player producing slight drag on the lineup to being one of its biggest assests simply by putting him where doing what he does best is most useful. This could also have a significant effect on the Drag Factor for the rest of the team, especially Josh Rutledge, by allowing the Toddfather to act as a kind of lineup protection. Guys like Rutledge, who don't have quite the plate discipline that Helton does, are much more likely to see fewer strikes if batting eighth, but Todd is still effective enough that you don't want to just put guys on in front of him. This move should mean more balls for Helton, and more strikes for the guys in the sixth and seventh spots.
The eye test certainly suggests that pitchers are nowhere near as afraid of Todd Helton as they used to be, but putting him in the eighth spot allows Helton to turn this into an advantage. At that point, pick your poison. Work around a guy who has one of the best eye's in the game (two of 'em in fact) or throw strikes to an excellent contact hitter that can still do damage.
This all essentially boils down to aggressiveness working against you in the eight-hole and working against Todd Helton all year. The Rockies have enough free swingers without trying to force their most patient one to be aggressive by batting him sixth. Putting his patience in the spot where it would be most effective would likely send a ripple effect through the whole lineup by dramatically reducing "Drag."
There is no way of getting around the fact that the winning team in every baseball game needs to get 27 outs. Every time Helton walks in front of the pitcher, he is creating more opportunities for Cargo, Tulo, and the rest of the gang (and himself) by prolonging the road to 27 outs for the opposing team. Todd Helton isn't the run producer he used to be but, in the eighth spot, he could be one of the toughest outs in the NL. If I'm right, and Helton thrives in that spot, getting outs in this lineup becomes an even more nightmarish task for opposing pitchers.
So let me say again (as promised) that this idea is not meant as a punishment for Todd Helton getting older. It is not meant to bury him in the lineup or insult his amazing career, it is meant to put him in a position to be a major factor in not letting the other guys get anything easy. Todd Helton has the perfect skillset to be a dominant eight-hole hitter, forcing the opposition to rethink its strategy, and likely giving the Rockies more at-bats per game. And more at-bats for this lineup is a very, very good thing.