Here is a link to my Sunday column about Michael Crabtree. The full column appears below:

He could change everything for the 49ers. Who is “he”?

Michael Crabtree, of course.

Crabtree will play today against the St. Louis Rams. Crabtree tore his Achilles’ tendon in May and has been a noncombatant ever since, and you know what that did to the San Francisco offense. Strictly Dullsville. Almost dead.

Crabtree is a top-10 receiver in the NFL. Well, let’s be prudent here. He was a top-10 receiver before his injury. It’s unknown what he is right now, but that will be revealed in a few hours. Obviously, he and the 49ers think he’s all the way back.

If Crabtree is all the way back, this is what we’ll see. He runs perfect pass routes. His routes are beautiful, a Shakespeare sonnet on grass. He has great hands, strong hands. He fights for balls. Some receivers wait for the airborne ball to reach them (A.J. Jenkins). Crabtree attacks the ball. He is stronger than most cornerbacks and when he fights them for the ball, he wins the fight.

He is a master of YAC. If you don’t know from YAC, you get a demerit. YAC goes back to the Jerry Rice days and it means “yards after the catch.” Crabtree is a YAC specialist even though he’s not a speed burner. It comes down again to his attacking attitude. He grabs the ball and tears upfield with that sucker tucked in his arms daring defensive backs and linebackers to bring him down. Not so easy.

He would be the best wide receiver on almost every team in the NFL, the best even though some are faster.

With him back — if he is back — the equation changes for the 49ers. They are struggling to be a wild-card entry to the playoffs, the sixth and final wild-card entry, the entry that limps into the party. You know that. Crabtree makes the 49ers a Super Bowl contender. Forget limping. They could be sprinting.

Today’s game is a good game for his return. The Rams can do some things well — special teams — but they are distinctly mediocre and with their crummy record, 5-6, they aren’t playing for much. Call this a training-wheel game for Crabtree, a game to steady himself on the road and get the feel of things. (Do kids still learn bike riding on training wheels?)

PCR (Pre-Crabtree’s return), the 49ers had two serious pass catchers, Anquan Boldin and Vernon Davis. Both are very good, but quality defenses and some not-so-quality defenses could shut them down. Especially Boldin, who is old, slow and a YAC zilch.

Here’s how it works with Crabtree on the field. Defenses no longer can double-team Boldin in their base packages. They must commit a quality defender to Crabtree, would be nuts not to. That frees up Boldin. And Crabtree’s mere presence creates more room for Davis. That’s obvious.

Even if the Niners don’t throw to Crabtree, opponents have to respect him as a legitimate threat. The Niners have not had a threat at his position all season, although they pretended to.

Crabtree on the field means defenses can’t load the box with eight defenders. Hey, I love using terms like “the box.” They make me feel like a football guy. I bet they make you feel the same way. I’m not exactly sure where the box begins and ends — I mean, there’s no actual box. For dummies like me, loading the box means the defense crowds a lot of guys near the line of scrimmage, sort of like a gang rumble.

So, what’s the deal with this newly-unloaded box?

It means Frank Gore will have room to run.

Why?

Because some former box loaders will be running after Crabtree, running scared. Think of it this way. Even against the lowly Redskins, Gore had nowhere to run. It’s like the Redskins dumped a huge sofa in — you got it — the box. Just about every time Gore ran, he knocked into the sofa, skinned his shins and fell down. Now, the sofa is gone and Gore could find himself cruising on a super highway. Think of him in full Niners’ gear in the diamond lane of 101.

And one more thing. Crabtree is Colin Kaepernick’s favorite receiver. The return of Crabtree could mean the return of Kaepernick.

You get the point. Crabtree matters.

That’s if Crabtree really is Crabtree.

Six months is a quickie recovery from an Achilles’, totally fast tracked. It gives you pause. The Niners obviously want him back ASAP because they must have legitimate in-house concerns about their ability to compete with some of their remaining opponents — Seattle, Arizona — without Crabtree on the field.

With the wild card so tight, how many games can they afford to lose and still have a chance for the playoffs?

I’m asking — not suggesting — if the 49ers are rushing Crabtree back out of worry. It’s something to consider although I don’t believe Crabtree or his agent would allow him to be rushed with so much future money riding on his health.

We will get answers today.

Now for our nature lesson.

The name Crabtree is short for crabapple tree. If you’ve ever tasted crabapples, you know they are sour and unpleasant.

Until today, Crabtree’s season has been sour and unpleasant. The 49ers are hoping a metamorphosis happens against the Rams, hoping Michael Crabtree emerges as a golden delicious.

For more on the world of sports in general and the Bay Area in particular, go to the Cohn Zohn at cohn.blogs.pressdemocrat.com. You can reach Staff Columnist Lowell Cohn at lowell.cohn@pressdemocrat.com.