The Arizona Cardinals have one of the most potent offenses in the NFL.Through eight games they are first in the league in total points, with 263, and second in the NFL in average points scored per game, at 32.9. They are also third in the NFL in total yards.Be it by land or by air, their offense has been very difficult for opponents to stop this season, with QB Carson Palmer, RB Chris Johnson and WR Larry Fitzgerald leading the way. Comments Share The 5: Takeaways from the Coyotes’ introduction of Alex Meruelo Derrick Hall satisfied with D-backs’ buying and selling Top Stories But halfway through each of Palmer, Johnson and Fitzgerald has been better than anyone would have expected, and they’re the main reason the Cardinals are 6-2 and leading the NFC West. Grace expects Greinke trade to have emotional impact Former Cardinals kicker Phil Dawson retires That trio, by the way, was named the third-best triplets in the NFL by NFL.com’s Dave Dameshek.3) Arizona Cardinals: Carson Palmer,Chris Johnson & Larry FitzgeraldPreseason rank: No. 24This mature trio might look like the casting call for a Cialis ad, but the vets are functioning at the highest level on NFL gridirons so far this season. (Did anybody see the Chris Johnson resurgence coming?)The Cardinals’ trio trails only New England’s Tom Brady/Dion Lewis/Rob Gronkowski and Green Bay’s Aaron Rodgers/Eddie Lacy/Randall Cobb, and is no doubt deserving of its high standing and improved ranking.Palmer is tied for the league lead with 20 touchdown passes, is first in yards-per-attempt, fourth in total passing yards and fourth in passer rating.Johnson is second in the league with 676 rushing yards, with his 4.8 yards-per-carry average being the highest he’s carried since 2009.Fitzgerald is fifth in the NFL with 55 receptions, which he has taken for 706 yards and seven touchdowns, which puts him on pace to set some career-high marks in this, his 12th season.Whether or not this trio, with each member being over 30 years of age, will continue to play at such a high level the rest of the season remains to be seen. Also, it’s possible that someone like John Brown — who is second on the team in receptions and himself having a very good season — could overtake Fitzgerald as the receiver in the group.