Two teams. Two trades. And about a hundred questions.

That’s where the Dallas Mavericks and Phoenix Suns stand after each fell behind 0-2 in their best-of-seven first-round playoff series. This wasn’t anticipated when each made blockbuster moves at the trade deadline that they thought would add the one veteran piece to put them over the top. Instead, neither may survive the first round, which would lead to a real interesting offseason.

Let’s start with Dallas, who acquired longtime Nets stalwart Jason Kidd in a midseason trade that netted New Jersey two first-round picks and speedster Devin Harris. That move was supposed to give the Mavs the veteran moxie they needed after their last two postseasons ended in disappointing defeats.

But thus far, Kidd has been a total nonfactor. Worse yet, he’s been savagely beaten by Hornets point guard Chris Paul, who has shown the nation why so many of us thought he was the league’s Most Valuable Player this year.

Paul’s averages on the series are eye-popping: 33.5 points, 13.5 assists, and 3.5 steals. He’s the first player to get at least 30 points and 10 assists in each of his first two playoff games, and only the second to have those numbers in back-to-back playoff games since 1990. (If you think former Nets and current Hornets coach Byron Scott isn’t enjoying watching Kidd get mauled, I’ve got some land to sell you under the Pulaski Skyway).

Kidd’s numbers, meanwhile, are pedestrian: 9.0 points, 8.5 assists, 6.5 boards. Forget triple-doubles — Dallas would be happy with a single-double at this point. The fast-breaking element he was supposed to add to the Mavs has been nonexistent since the first half of Game 1, as Dallas’s inability to stop the Hornets has killed any chance of getting an advantage in numbers going the other way.

Kidd’s inability to contain Paul has been at the forefront, as the smaller, speedier Hornets repeatedly navigate around him and into the paint. The irony is that in order to acquire Kidd, Dallas gave up the exact type of player who defends Paul best — the quick, agile Harris.

If Dallas’s season does end in the next week at the hands of the Hornets, the question is what cards are left to play next. And one keeps returning to the only plausible conclusion: They’re going to fire coach Avery Johnson.

Rightly or wrongly, the blame for the Mavs’ playoff disappointments has been laid at his feet. In particular, Dallas’s upset loss to eighth-seeded Golden State a year ago has put a black mark next to his name. Many blamed Johnson for starting Devean George in the opener as an adjustment to the smaller Warriors, rather than making the underdog blink first.

But the bigger reason that Johnson will be the one to go is that it’s the only option left. They’ve used all their assets — draft picks, young players, etc. — to build the team they have. The only remaining alternative is to see if somebody else could coach it better.

Unfortunately, it was the trade that really did them in. Suddenly, the Mavs are an old team with a bad cap situation, limited depth, and no draft picks. They’ll stay a playoff team as long as Dirk Nowitzki remains a superstar, but one suspects their days as top contenders are coming to a close.

Feeling only slightly better than the Mavs are the Phoenix Suns, who dropped their first two games to San Antonio in gut-wrenching fashion, as our Martin Johnson discussed yesterday.

Like Dallas, Phoenix made a huge midseason dice roll in a “win today” move: They traded forward Shawn Marion and guard Marcus Banks to Miami for center Shaquille O’Neal. O’Neal gives them two advantages: First, he can guard Duncan, who has terrorized the Suns in past playoff series, and second, his addition allowed Amare Stoudemire to move to his natural power forward spot, where he’s thrived.

Nonetheless, the Suns will have to ask some hard questions if they fail here. O’Neal is clearly in decline and has two years left on his contract at $20 million a year; undeniably then, this spring is Phoenix’s best and possibly only shot at winning it all. Additionally, the Suns are facing the one team they were constructed to beat — if they still can’t top the Spurs now, what does that say about their midseason face-lift?

Like the Mavs, the Suns suddenly face a lot of age issues. In addition to the 36-year-old O’Neal, two-time MVP Steve Nash is 34, defensive ace Raja Bell is 31, and forward Grant Hill is 35 and has a groin injury that’s limited his effectiveness in this series.

Hill’s injury made Marion’s absence particularly notable, as he used to be the Suns player charged with defending Spurs guard Tony Parker. The idea behind the trade was that Hill could take over that role; but with him on the shelf again, the speedy Frenchman has flambéed Phoenix’s defense to the tune of 58 points in two games.

So, instead of O’Neal leading Phoenix to the promised land, it appears new Suns general manager Steve Kerr may have gone all-in on the first hand and found himself short a card.

With those trades as the backdrop, both Dallas and Phoenix are halfway to elimination and face must-win games Friday night. Each is good enough that they might get back up off the mat and make a series of it. But as things stand now, both appear to have taken giant risks that blew up in their faces. And if that conclusion holds, there will quite a reckoning this summer.