A friend who is a financial planner taught me a good stock isn’t really a good stock unless you can buy it at a price that allows you to make money.

Here’s how that’s analogous to NBA basketball: Rudy Gay is a good player and good players who aren’t old are seldom available in trade. Yet I don’t know that Gay will be worth the paycheck or the trouble the Toronto Raptors went to to acquire him.

The Memphis Grizzlies sent small forward Gay to Toronto on Wednesday night in a three-team deal that brought them power forward Ed Davis from the Raptors, plus Tayshaun Prince and Austin Daye from the Detroit Pistons.

I found this a smart deal for the Grizzlies, a small-market team that couldn’t afford the bill they’d be paying under the new, far more punitive, luxury tax. I think Prince still has some mileage to replace Gay as the Grizzlies’ small forward. Davis, still playing on the rookie pay scale, is a fine replacement for Marreese Speights, who the Grizzlies sent to Cleveland in another payroll trim. Daye is a write-off.

Now look at this deal from the Toronto angle: The Raptors are obliged to pay Gay $37 million over the next two seasons. That’s “great player,” money. Gay isn’t a great NBA player. Never has been, likely never will be. So why are did the Raptors do this?

Buzz. That’s the only thing I can figure. Toronto is the fourth-largest city in North America, and there’s plenty for a sports fan to do. The Blue Jays have made some major moves that make them an American League contender. The Maple Leafs are an almost religious experience to their core fans. And the NFL Buffalo Bills are just down the road and play one regular-season game annually in Toronto.

The Raptors were in danger of being an afterthought up there, and their general manager, Bryan Colangelo, might be running out of time. So it appears he did something bold and flashy Wednesday, grabbing Gay, who he considered drafting with the No. 1 pick in the 2006 draft.

Instead of choosing Gay, Colangelo went with Italian big man Andrea Bargnani. There was no clear best pick in that draft (as evidenced by the Charlotte Bobcats choosing Adam Morrison – a complete bust – with the third pick). The Raptors owe Bargnani about $22 million over the next two seasons. He’s a good player being paid like a great one.

Notice a pattern here?

A good stock is really a good stock only if you can buy it at a price that allows you to make money. Likewise, Gay and Bargnani might be good players, but they’re paid like great players. The math doesn’t work.

Had the Bobcats acquired Gay, I would have applauded their aggressiveness, but I also would have questioned their judgment. I assume had Gay ended up here, it would have cost the Bobcats rookie Michael Kidd-Gilchrist. I don’t know that adding Gay would have been worth not exploring Kidd-Gilchrist’s potential. And paying Gay $37 million over the next two seasons likely would have precluded any other significant moves in Charlotte.

I’ve suggested Pau Gasol would be a great move for the Bobcats if the Los Angeles Lakers are willing to trade him. Gasol makes even more than Gay ($38 million-plus over the next two seasons) and he’s older than Gay. The difference is power forward/center Gasol would address the Bobcats’ clear weaknesses (no post scoring, poor rebounding) and Gasol has proven himself (NBA titles and All-Star appearances) in ways Gay hasn’t.

I doubt Gasol will ever be a Bobcat. I’m not disappointed Gay won’t be a Bobcat. A good stock is a good stock only when it’s purchased at the right price.

Five passing thoughts on

the NBA and the Bobcats:

•  Sounds like Brandon Roy’s efforts to overcome knee injuries and extend his career are about over in Minnesota. Sometimes you just have to make peace with your body.

It doesn’t particularly matter whether the Bobcats avoid last place in the Southeast Division, but this injury to Glen Davis makes the Orlando Magic pretty vulnerable the rest of the season.

•  Of course Boston Celtics general manager Danny Ainge is going to say he won’t break up Kevin Garnett and Paul Pierce at the tail end of their careers. But if you think he’s not taking and making calls all over the league, you’re being naïve.

•  This talk that the Grizzlies squandered a chance at winning a championship implies they ever were going to win it. I like that team, but I never saw Memphis advancing more than two rounds in the Western Conference playoffs.

•  It’s classy that Mark Cuban wouldn’t trade Dirk Nowitzki against his will. But I wonder if the Dallas Mavericks are the best place for what’s left of Nowitzki’s basketball career.