If Jay McGwire’s proposed book goes to press, his brother’s reputation (or what’s left of it) will be ruined.

Deadspin printed some excerpts of the proposal, which has made the rounds of publishing houses. “The McGwire Family Secret” will not help Big Mac’s Hall of Fame chances.

The proposal fleshes out what has already been reported about Mark McGwire and his brother, a former bodybuilder and admitted steroid abuser.

The long and short of it: Jay claims he introduced Mark to steroid and human growth hormone use in 1994 and Big Mac went “all in” on the stuff for the next four years, until he shifted to andro as his training fuel.

Here is how the San Jose Mercury News summed it up:

Forget about friends and enemies. With a brother like this, who needs Jose Canseco?

Certainly not Mark McGwire. According to the Web site Deadspin, Jay McGwire, Mark’s estranged and strange brother, is shopping a tell-all book in which he says Canseco couldn’t possibly have gotten Mark started on steroids in the late 1980s.

And why? Because Jay got Mark started in 1994. “Shortly after I won the Contra Costa Bodybuilding Championships in May of 1994, Mark took the plunge,” Jay writes. “I accompanied him to Sacramento where we met with my supplier and trainer, who explained to him how the different drugs would work on his body and answered a myriad of questions from Mark. Given Mark’s curiosity and lack of knowledge about steroids I saw from Mark, I would be shocked if Mark did something like what Jose Canseco claimed happened back in the early years.”

Now there’s a helpful character reference.

Jay also says he and Mark are no longer on speaking terms. Who’da thunk?

Mark McGwire has pretty much gone undercover. Something tells us he won’t do David Letterman again any time soon:

TAKING AIM AT THE ROCKET

Admitted steroids dealer Kirk Radomski has penned a new tell-all book (“Bases Loaded,” Hudson Press) that Roger Clemens won’t like.

Radomski backs Clemens accuser Brian McNamee 100 percent.

“If Brian was such a bad person why did Andy Pettitte back him?” Radomski told ESPN.com. “Why did Chuck Knoblauch back him? You let a guy you don’t trust and you don’t respect stay in your house, and be around your family. And be around your kids.

“He admits his wife got a shot [of human growth hormone] in the bedroom. Think about this, he let someone go in a bedroom with his wife and inject his wife. And you didn’t trust the guy? If he didn’t trust the guy, he would have knocked the guy out. That would have been it. But he let him do it. What does that tell you?”

(BTW, at the rate these steroid books are being written, the big bookstore chains will have to create a separate section for them. What’s next, Bill Romanowski’s “Steroids For Dummies”?)

Now, on a lighter now . . .

MYSTERIES OF THE UNIVERSE

Questions to ponder while wondering why Chris Mason has been a better goaltender on the road than in Scottrade Center:

• Was Hank Iba spinning like a rotisserie chicken as two teams played run-and-gun basketball on his old court?
• Shouldn’t Mizzou work the clock just a little bit after taking a double-digit lead on the road?
• And since the Tigers like to press and trap on defense, shouldn’t their offense be better prepared to handle traps and presses?
• Why haven’t the Phillies locked Ryan Howard into a long-term deal? Doesn’t that team realize the price will only go up?

QUIPS ‘R US

Here is what some of America’s leading sports pundits have been writing:

Jerry Greene, Orlando Sentinel: “With all the problems Notre Dame football brought on itself, now it has to fight unfounded media rumors that Charlie Weis is going to be dumped for  Jon Gruden. Shouldn’t  Urban Meyer tell Gruden to get in line?”

Jeff Schultz, Atlanta Journal-Constitution: “There are six Super Bowl winning coaches out of work: Mike Holmgren (hiatus), Mike Shanahan (fired), Bill Cowher (hiatus), Jon Gruden (fired), Brian Billick (fired) and Tony Dungy (retired). Wonder what the odds were of that.”

Rick Reilly, ESPN.com: “Saw a quote the other day from Clippers owner Donald Sterling that made me choke on my tuna fish. After the last-place-yet-again Clippers absorbed another loss, Sterling told the L.A. Times: ‘I don’t take too well to losing.’ Are you kidding, pal? You take it better than anybody in NBA history! All you DO is lose! You are to losing what the Titanic was to sinking! Over 28 years, you’ve done almost nothing to stop losing, because the Clippers to you are just another real estate investment that you’ve watched go from $13 million when you bought it in 1981 to an estimated $294 million now. That’s fine. Congratulations. Light up a Cohiba. But just don’t tell us you don’t do losing. You do losing better than Oprah does gaining!”

Scott Ostler, San Francisco Chronicle: “Plaxico Burress was given a free truck from a dealer in exchange for agreeing to schmooze and sign autographs for customers. Burress loaned the truck to a cousin, who got into a highway gun fight, and the truck was wrecked. The dealer complained that Plax never showed up for the autograph-signings. Of course he didn’t. How would he get there?”

Dan Daly, Washington Times: “Almost every NFL stadium has a system that enables fans to text message security if they’re bothered by unruly behavior. Just wondering: Does this behavior include roughing the passer?”

MEGAPHONE

“I’m in a new part of my career, and I’m excited about rehabilitation and different challenges. The tough part is you’re not experiencing something you love to do. But you get over that and you focus on what you’ve got to focus on and you just say ‘OK, well, it happened. We’re moving on.’”

Patriots quarterback Tom Brady, in a interview with Fan 590 in Toronto.

ELSEWHERE ON STLTODAY.COM

Look at the power of the Internet! After I wrote about the Blues’ need for better goaltending, Mason shut out the explosive Blackhawks. Good to see the guys are reading the site. Also, Hockey Guy spoke out on behalf of fighting. Opponents of fighting were doubtlessly horrified by Wednesday night’s Blues-Blackhawks game.