HOUSTON – The plan for Michael Crabtree was supposed to be modest.

The 49ers figured to ease the late-arriving rookie onto the field by lining him up at the relatively easy-to-learn slot position. Coaches said that if everything went well, Crabtree could see as many as 10 to 12 snaps in the game following the 49ers' bye week.

"It's going to start small," Mike Singletary said the day Crabtree finally signed his contract. "A small role here and there, figuring out ways to get him on the field."

Two and a half weeks later, however, Crabtree is on the verge of a far more ambitious coming-out party.

There's a good chance he'll start today's game against the Texans. Even if he doesn't, he'll see just as much playing time as early-season starters Josh Morgan and Isaac Bruce, something on the order of 30 snaps.

Asked if he expected Crabtree to deliver big plays against the Texans, Singletary on Friday said, "Absolutely. That's why he is playing."

The expectations went from small to soaring in the span of a bye week. What changed?

Following a 10-week absence, Crabtree arrived at team headquarters far more prepared and polished than anticipated, and he thrived during a three-day cram session over the team's bye. The more wide receivers coach Jerry Sullivan and offensive coordinator Jimmy Raye threw at him, the more the rookie absorbed.

"(He) had a starting point that was better than what I had anticipated in terms of him understanding the formations and understanding the route tree and the plays and how they fit together," Raye said. "He's a quick study that way."

The education of Michael Crabtree began in July when the rest of his teammates reported for training camp. While the 49ers and Crabtree's agent, Eugene Parker, slipped into a cold war over the rookie's contract, Crabtree began preparing for his eventual debut with the single-minded focus of a boxer getting ready for a heavyweight fight.

In fact, his training regimen included boxing, skipping rope and running three or four miles a day. He did countless pushups and sit-ups. He hired a personal chef.

When he ran pass routes, he would do so as if he were in an NFL game. He spent entire afternoons catching balls on the sideline with two feet – not one, as in college – in bounds. He practiced exactly where he would make his cut on third-and-eight, third-and-10 and third-and-12 situations. He even coaxed Saratoga neighbor Trent Dilfer, a 14-year NFL veteran, to join him for two August workout sessions at Valley Christian High School in San Jose.

Crabtree has yet to take the field for an NFL game, but he said he's already run countless routes against NFL defenses.

"In my head," he said by way of explanation. "I had friends out there playing Cover 2 and just having fun."

And he's been studying his opponents. When Crabtree finally reported to the 49ers, team officials were pleasantly surprised that he had already broken down each of the NFC West cornerbacks by watching games on his computer. Crabtree spent nearly every day he missed imagining what he would do when he finally joined the 49ers, and it paid off as soon as he arrived.

"He has an uncanny knack to conceptualize the picture quicker than most young guys, so the words that paint the picture of the play, he gets it pretty quickly so far," Raye said.

After signing his contract Oct. 7, Crabtree was given a spot on the 49ers' scout team. At that point, his physical readiness became clear to coaches.

It was the following week – when most of the 49ers had left town for the bye weekend – that Crabtree convinced the 49ers he was ready for the mental part of the game.

Crabtree and Sullivan, an 18-year veteran and a real stickler for details, would disappear into the film room for hours and then emerge to apply the classroom work to the practice field. Morgan also was on hand to give Crabtree live demonstrations of how routes were run. Alex Smith threw passes one day. Assistant trainer Nate Breske, a former quarterback at Northern State in South Dakota, threw to him the next.

"He has a football sense, I guess you could call it," Smith said. "He has a good understanding for what we're doing, how the offense works – especially for as long as he's been here."

Read Matthew Barrows' archives and blogs at sacbee.com/sf49ers.