In 1976, after a distinguished football career at St. John's High School, Robert Jagers decided to try to make it big in the college ranks. Not just for publicity, or an affluent booster club or 80,000 people in the stands. Like anyone with a gift, he wanted to find out how far his talent could take him.

Now, after five years at Penn State, (a knee injury in his sophomore year cost him a year on the football field), Jagers has a Sugar Bowl and a rewarding college career behind him. But the former high school all-America still doesn't know the answer. He knows he's good enough to play on one of the nation's best college teams. Good enough to be its captain. But how good is that?

Jagers, 22, graduated last week with a bachelor's degree in psychology and rehabilitative education. Graduate school is beckoning. But he's still goint to test his athletic limits. Knee injury aside, he says that if he isn't chosen in the National Football League draft April 28 and 29, he'll offer himself as a free agent to the teams that have expresses the most interest in his services.

Serious on-campus scouting is under way.The Tampa Bay Buccaneers ran Jagers and two teammates through sprints and agility tests. Jagers also traveled to Shea Stadium to take the New York Jets' physical with 10 other Penn State players and hundreds from around the country. He's been contacted in one way or another by half the 28 NFL teams.

There's one person who thinks Jagers might be wiser to consider graduate school, work on his long-range plans for a ranch for needy kids -- and take care of his knee. That's Joe Paterno, the Penn State coach, whose reputation for treating his players as mature individuals persuaded Jagers to decline offers to attend Ohio State and Alabama.

Paterno says if Jagers is drafted in the top two or three rounds, he should play. If not -- and Paterno won't make any predictions -- he thinks his center ought to give the idea serious thoughts before offering himself as a free agent. After the draft, when things have quieted down, Paterno will tell Jagers what he thinks.

Will it make a difference?

"No," said Jagers, without hesitation. "I'm not going to quit until I try. It's worth giving a try until it's time to hang it up. The only way to find out that point is to reach it."

Paterno has seen that ambition before. "That magnet has a lot of pull," said Paterno. "It's a game these people (the pro teams) play with the kids. They tell people what they want to hear. But I tell them all, 'Don't worry about it. If you get a job opportunity or grad school, take it.'

"With Bobby . . . I'm not sure he's smart giving it a shot. He's got a knee that's good enough now to have a fine life. Why go in there and bang it around for a couple of thousand dollars?

Jagers was firm. "I've seen too many guys make it going the free-agent route," he said. "I'll negotiate with whoever's interested. I'd just like to know if I could play at that level. If football doesn't work, okay. I'm not going to put it into my mind that's it, the last road to go.The doors are still open. There's graduate school. But I'd like to try it."

What about the knee? Jagers missed a year with an operation and says the knee is fully recovered.The tests with the Buccaneers and the Jets went fine. His acceleration was good. True, other men who played with similar problems are now walking around on gimpy knees. But a possible limp 30 years down the line is an abstract notion for a man courting the NFL.

Jagers' pursuit of football distinction has been supported by his parents, who keep detailed scrapbooks in their Shepherd Park home. The clippings tell the story of one of the most highly recruited scholastic players in the East. He was all-Met, all-prep, all-Catholic in his junior year at St. John's and all of the above plus all-America his senior year. He was courted not only by Alabama and Ohio State, but also by Tennessee And Maryland.

Jagers' father, retired Army captain Samuel Jagers, a ROTC instructor in the District school system, has not missed a game in the last two years. His mother Carole has missed only a few. Jagers has a younger brother Todd, a sophomore at the University of the District of Columbia, and twin sisters Staci and Traci, eighth-grade students at Our Lady of Lourdes. His career decision has received their wholehearted support.

"Whatever Bob wants," said Carole Jagers, "we want, too."

Off the football field, Jagers has been deeply involved in tutoring children with learning disabilities at a home called Strawberry Fields, in State College, Pa. The home is funded by the state and staffed, in part, by students from the university. Jagers works twice a week with six children living at the home, taking them to workouts and practice sessions.

"I guess you could say it (the home) is two steps from society for them," Jagers said. "The idea is to start interacting them with the world. I worked with the program last summer, and it worked well. They (the supervisors) want the kids to develop athletically, as well as in other areas. Some have real problems, others are just slow learners, but they all enjoy things like going down to the weight room or going to martial arts classes at the school.

"The idea is to get them away from the regimentation. Let them know that someone cares, have someone tell them that this is what they can do to make themselves a better person."

Jagers envisions someday running a ranch for foster children.

"I see a foster ranch, a group home, running it myself," he said. "What I'd do with it would depend on the need of the community. I want to go where the need is."