BY JIM THOMASTuesday, May 15, 2012

With the rookie minicamp come and gone, the Rams now reach the heart of their offseason program. Starting today, the team holds the first of 10 full-squad practices known as OTAs (organized team activities) with those sessions spread over the next four weeks. Then comes the full-squad minicamp, June 12-14.

"As we told the 'varsity' this past week, we're going to start again from day one with the installation" of his program, coach Jeff Fisher said. "And by the time we're done in mid-June, we will have installed absolutely everything.

"Then we're going to do it again when training camp starts. So when they come and report to training camp, they'll know exactly what to expect through camp. The only difference is we're going to put some pads on at times."

No pads are allowed during the spring OTAs and minicamps.

By "varsity," Fisher jokingly was referring to the team's veterans. As for the 10 draft picks and 24 undrafted rookies who participated in the rookie minicamp over the weekend, they'll just have to catch up and keep up in terms of the playbook and conditioning.

"There's a lot of work that needs to be done" by the rookie class, Fisher said. "This is a good class. They're working good together."

The Rams added another rookie to their ranks Monday, signing wide receiver Mike Campbell of Temple to the offseason roster. Campbell had participated on a tryout basis at the rookie minicamp over the weekend.

But three rookies left Sunday and can't come back for a while: running back Isaiah Pead of Cincinnati, punter Johnny Hekker of Oregon State and tight end Cory Harkey of UCLA. Pead was a second-round draft pick; Hekker and Harkey were signed as rookie free agents.

Their learning curve will be steeper because their colleges are on the quarter system, with school still in session. Per league rule, Pead, Hekker and Harkey can't return to Rams Park until final exams are complete at their school.

Hekker, who's trying to fine-tune his mechanics to develop greater consistency, said he doesn't expect to return to St. Louis until June 15.

By that time the veterans will have departed for the summer; the rookies will have two additional weeks before their pre-training camp break begins.

Pead, whom the Rams are counting on to be the top backup to Steven Jackson at running back, can't return until June 7. That will allow him to take part in one or two OTA sessions at the end of that week, as well as work for the entire week of the full-squad minicamp.

Cincinnati is "changing next year back to semesters just to kind of clean up this process," Pead said.

Over the weekend, the rookies got a heavy initial dose of the offensive and defensive playbooks. There was a lot of installation during a three-hour meeting Friday night, then more Saturday morning before the players hit the practice field.

"I was pleasantly surprised with how they were able to absorb all of the information and bring it to the practice field," Fisher said following Saturday's practice.

But it's definitely an adjustment process for the incoming players. They may have mastered a college offense or defense, but at the NFL level you're talking about the gridiron equivalent of a Ph.D.

"This is truly professional football, and these coaches, they're extremely smart and they've got some excellent plays in place for us," said center-guard T-Bob Hebert, a rookie free agent from Louisiana State. "My goal is, I just want to study as hard as I can. I don't want to hold myself back with mental issues."

Although generally pleased with what he saw, Fisher has been in coaching too long to make sweeping pronouncements about rookies based on two days and approximately three hours of practice time. Also, any early impressions are subject to change today, when the rookies are joined by the "varsity" on the practice field for the initial OTA.

As is the case with the minicamps, the OTAs are not open to the public. In fact, only select OTAs are open to the media.