Why do the Arizona Diamondbacks want to trade Justin Upton anyway?

Some Detroit Tigers fans openly asked the question that's been posed by many others Monday, after FoxSports.com's Jon Morosi reported Detroit and Arizona had engaged in talks involving pitcher Rick Porcello.

Morosi didn't indicate whether Upton — who invoked his no-trade clause to block a deal to Seattle last week — was part of the discussions.

But should the Tigers pursue a trade for an outfielder who appears to have worn out his welcome in Arizona?

"I think he's trouble, a headache waiting to happen. He has all the physical tools, but, unfortunately, does NOT know how to play the game. Much like DYoung, he has no plate discipline. And, he's been a headache to Gibson/Trammell in AZ. If he cannot get along with those two, I don't see him getting along with Leyland … " — Galloping Greg

"Forget Upton … Don't need a headcase in the OF whose performance is too up and down. SS is where the Tigers have the most need. If they trade Porcello, then they better get a young, slick-fielding SS who can hit and has some speed back in the deal." — enrapport26

Upton, 25, is a career .278 hitter who has at least 17 home runs in each of the past four seasons. In 2011, he hit .289 with 31 homers and 88 RBI.

He's signed through the 2015 season, scheduled to make $9.75 million in 2013 and more than $14 million the following two years.