The majority of fantasy players are going to get sucked into thinking whoever plays at lock for the Broncos will pick up the majority of Parker's points and minutes. In my opinion this is wrong and lets dive into why.
I think early rounds last year showed a sneak peak into what will happen with the Broncos pack. In 2015 Parker averaged 62.5 points in 62.7 minutes, pretty much bang on with his career PPM. In the first 10 games of 2016 Parker averaged 59 minutes yet only 51.5 points. To figure out why this happened we can see average tackles(34.2 down to 29.5) tackle breaks(1.9 per game down to 1.7) and offloads (1.9 down to 1.3) being the biggest cause. His run metres stayed reasonably consistent. The biggest reason for this sudden drop in stats was not due to age, but due to a different role within the team. Only watching the first 9 games of the year I noticed a trend among with Parker and McGuire.
In previous seasons Parker did most of his defensive work from marker or as the "A" defender(for those that are unsure what this means I have attached a picture above) with McCullough acting as the other marker or "A" defender if the tackle was made wider. However in the first 10 games, whilst Parker still spend time defending at the "A" position, the majority of his time was spent as the "B" or "C" defender with McGuire filling in as the "A" defender on the majority of plays. This led to more defensive work being funnelled at McGuire and McCullough with Parker missing out on those "easy points."
Onto the missing tackle breaks and offloads. The explanation for this is much simpler. In previous seasons Parker took most of his hit up on 3rd and 4th tackles when the defense was retreating giving him a chance to hit the line at pace and work some magic, either with an offload or tackle bust. 2016 saw Parker taking the majority of his hit ups on 1st and 2nd tackle when the defensive line is set and the forwards job is to hit the soft spot behind the markers and get a quick play the ball, rather than trying to make something happen offensively. This extra work however was not taken over by McGuire, but covered by the emergence of the young Broncos forwards (Ofa, Pangai Junior, Arrow).
TL;DR Regardless of who is wearing the number 13 jersey for the Broncos they will not replace Parker's output if last season is anything to judge by. If you are chasing base stats and consistent scoring lock in McGuire. If you want upside pick one of Ofa, Pangai or Arrow and hope for the best.
Great analysis MS, however with Parker gone and also their third prop in Jarrod Wallace I think there is a lot of value. For starters, McGuire is locked into my side, he averaged 48 points in 57 minutes last year, and I believe he and McCullough are the best defensive players the Broncoes have so would assume they line up as "A" defenders again. Even if McGuire only averages between 65-70 minutes he will average 55 which is gun status. I also think there will be value in Pangai Junior who averaged 22.5 in 24.5 minutes last year. This will probably push up to 35 minutes per game and being another year older he might have more confidence to get the offload going and should break a few more tackles. Then there is Jai Arrow who averaged 23 in 26 minutes, whom I suspect will play around 40 minutes per game and possibly more. He will also be the one to pick up more minutes when the inevitable injuries hit so should be a good cash cow as well. I will possibly start with all three depending on other value I see, possibly in the Cowboys Front Row with Kaufusi/Spina/Hoare.