The Dallas Cowboys' bust is blowing up with the New York Giants.

Tight end/goofball Martellus Bennett, who didn’t score his last three seasons in Dallas, has become the first player in Giants history with a touchdown in his first three games for the franchise. He already has more receiving yards this season (185 on 15 catches) than he did all of last season. Eli Manning has already thrown Bennett as many touchdown passes as Tony Romo did.

We’ll let ESPNNewYork.com gush about how great an addition Bennett has been for the Giants. Let’s assess the blame for why he never approached his immense potential with the Cowboys.

Don’t buy the bull about there not being room for both Jason Witten and Bennett to be weapons in the Cowboys’ passing game. The New England Patriots are proof that two talented, versatile tight ends can thrive together in an offense. And the Cowboys, a middle-of-the-pack team in points scored, sure could have used another stud.

The Cowboys didn’t draft Bennett in the second round simply to have an offensive tackle who was eligible to catch the occasional pass. They expected him to be the dynamic downfield and red-zone threat he’s become with the Giants. That was the buzz after Marty B. was All-Alamodome before his second season, putting together a personal highlight reel in training camp.

But Bennett never made a difference in Dallas’ passing game. How much of the fault for Bennett’s failure with the Cowboys should fall at the feet of the Garrett brothers?

Coaches get paid to motivate players and maximize their potential. Head coach/offensive coordinator Jason Garrett and tight ends coach John Garrett never figured out how to do that with Bennett, an all-time free spirit whose wavering focus on football could be a source of great frustration.

Bennett didn’t develop under the Garretts’ guidance. He regressed.

Bennett certainly shoulders a large share of the blame. He dropped too many passes. He ran too many sloppy routes. He moped too much, assuming he’d be nothing but a bit player while buried underneath Witten on the depth chart and the Garrett/Romo tree of trust. And he treated his final season at Valley Ranch like a prisoner waiting on his parole date, all but marking off the days in his locker stall.

The chicken-and-egg debate about Bennett’s days in Dallas: Did he not get many opportunities because he failed to capitalize on the ones he did get, or did he not capitalize because he didn’t get enough opportunities?

Marty B. has been far from flawless with the Giants, but Manning and the New York coaches have been rewarded handsomely for showing faith in the physical freak. He’s dropped three passes – two that could have been touchdowns – and drew his quarterback’s wrath for quitting on a route just before halftime in last night’s rout of the Panthers. But his production has still been outstanding, catching 15 of the 23 balls thrown his way, including the game-tying touchdown last week after two drops against Tampa Bay.

The Cowboys basically gave up on Bennett as a receiving threat, focusing on what he wasn’t (read: a Witten-like technician). They let a phenomenal talent go to waste.

And now it’s the worst-case scenario for the Cowboys: Their bust is booming for their biggest rival.