1) In Parenteau's two seasons with the Islanders (2010-2012), Tavares scored better with PAP at 5v5 than without.
Tavares without PAP: 1.73 pts/60, 0.73 goals/60, 8.93 SOGs/60 in 900 minutes
Tavares with PAP: 2.27 pts/60, 0.91 goals/60, 9.07 SOGs/60 in 1587 minutes
Tavares with Moulson: 2.18 pts/60, 0.87 goas/60, 9.18 SOGs/60 in 2144 minutes
Zone-starts were nearly identical for Tavares with PAP as they were for Tavares with Moulson. Tavares had somewhat tougher zone-starts away from PAP than with him, but not nearly enough difference to account for the half-point discrepancy.
Keep in mind a lot of the time the line was Moulson-Tavares-PAP, as Moulson and Tavares were typically together at 5v5. Isles now have Ladd and Lee as left wing options, each similar in some ways to a younger Moulson, who regularly scored near 30 pts at 5v5. (Ladd broke 30 seven consecutive seasons before managing 26 last season; Lee impressed with 30 in 2014-15, before last season's disappointing 19-point campaign at 5v5.)
2) Parenteau has been taking shots and scoring goals with more regularity since leaving the Islanders.
With the Islanders PAP scored at a 0.55 per-60 rate at 5v5. The next two seasons, with the Colorado Avalanche, his rate soared to 0.85. Last season he enjoyed a 0.74 pace with the Toronto Maple Leafs. His climb in goals rate is largely due to an increased shooting percentage, but his SOGs rate has also surged from sub-8.0 with the Isles to greater than 9.5 each of the past two seasons, with the Habs and Leafs.
3) Parenteau is coming off a very good 5v5 season with Toronto.
He led Leafs forwards (minimum 500 minutes) in pts/60 at 5v5 (1.72) and total 5v5 points (28, which was six more than any other Leaf forward), and had solid Fenwick (52.1%, 3.0 relative) and corsi (53.7%, 3.1 relative) numbers, even considering his favorable zone-starts.
At 33 years old one would imagine Parenteau's numbers are bound to take a dive in the next three to four years, but with fewer than 500 NHL games played there's a good chance his body will hold up at least for his one-year contract with the Islanders.
4) In his two seasons with Colorado, four of the five high-scoring forwards had better corsi numbers with PAP than without him.
Duchene 50.6% with, 47.6% without (850 minutes with)
O'Reilly 53.2% with, 49.2% without (340 minutes with)
Landeskog 54.1% with, 48.8% without (300 minutes with)
Stastny 53.0% with, 48.6% without (300 minutes with)
MacKinnon 44.0% with, 47.4% without (180 minutes with)
So aside from the smaller sample size with MacKinnon, the Avs enjoyed a shot-attempt advantage with PAP on the top two lines, whereas the scoring forwards appear to have been out-attempted universally without PAP on the ice. This is similar to the effect we saw when Grabovski had a chance with scoring forwards, such as Kessel, Tavares, Okposo, Lee, and Strome, though not as dramatic.
5) Parenteau hasn't been particularly good on the power play the past four seasons.
John Tavares plays a lot of minutes, so his wingers need to play a lot at 5v5. With a 5v4 man-advantage, Parenteau is 2.57 pts/60 since leaving the Islanders. (For reference, Josh Bailey is 8th among NYI forwards during that time span, at 2.67.) PAP doesn't kill penalties, so the Isles can load him up with 5v5 time, while they give a younger player with more power play potential (such as Pulock, Strome, or Barzal-- or two of the three) a spot on the first power play unit as a right-handed shot. Isles may be smart to do likewise with the left wing, setting Ladd with Tavares for 5v5 while saving Lee's energy for PP1, or vice-versa. The more energy wingers have to cover for Tavares on the back-check, the more Tavares can use his energy to attack.
At $1.3M, PA Parenteau is set to be the 11th highest-paid forward for the New York Islanders. He may very well outperform more than a few NHL wingers earning over $5M this season if he plays with Tavares at 5v5.