We all know about one Grand Rapids, Mich., citizen becoming a free agent Jan. 20. Now meet Alan P. Hartwick of Grand Rapids, self proclaimed "free agent fan."

After 20 years of living(?) and dying with the Chicago Cubs, Hartwick, 25, sent out a letter to executives of the 28 major league baseball teams: "At this moment I am a fan without a team" and will sign a contract with the club "that makes the best offer for my services."

"All the Cubs have given me over the years," he declared, "have been a couple of season schedules and games postponed because of darkness."

If the players can maneuver now for best offers, says Hartwick, "Why can't a fan do this - choose his own team? We know how much players mean. How much does a fan mean?"

One reply reported Hartwick. General manager Bing Divine of the St. Louis Cardinals "sent me a pennant, a jacket and a bumper sticker. It was nice, but I expect more."

Coincidentally, the Cubs announced this week they have more than doubled their eight-man scouting force, to 17. To dredge up new fans?

Hartwick - here we go again, the ubiquitous media, he's a newsphotographer for a Grand Rapids TV station - pledges his undying loyalty to the team that signs him, but as he has already demonstrated, sports loyalty can be tenuous. Another case in pont:

Super Bowl MVP Fred Biletnikoff.

Ever get back to your hometown of Erie, Pa.? the sticky-fingered Oakland Raider was asked, and replied: "No." I'll never go back to Erie. They can have Erie. I hope it drops in the lake. I just don't like the people. I don't like the way they treated me. I feel for what I've accomplished and done for Erie, I haven't gotten anything in return . . . They wanted me to go back there two years ago for a banquet but they wanted me to pay my way. That's Erie, Pa. A great town" . . .

If Oakland is Biletnikoff's kind of town, he can have the element in the crowd of 15,000 who turned Monday night's civic salute to the Raiders ugly.

"Malicious, mean sort of stuff." as a police spokesman said, marred the doings in and outside the Coliseum where the Super Heroes took their bows. At least eight persons were injured and 10 arrested, as roving groups of teeners beat people, several car windshields were smashed and purse snatchers and pickpockets plied their trade. And the usual complement of drunks cavorted . . .

Is Florida State still Biletnikoff's kind of place? Seminole football coach Bobby Bowden has reinstated Mike Shumann, whose 102 passes for 1.625 yards and 10 touchdowns surpassed Bilenikoff's FSU marks before Shumann was cut from the squad following an arrest for selling cocaine to an undercover agent prior to the 1976 season. Given court probation, "Mike came to me on Monday," Bowden said. "After talking with him, I've decided to give him another chance," and he'll play as a senior in '77 . . .

Oakland again, Charlie Finley again. The Major League Players Association filed grievances against the A's yesterday on behalf of players Tito Fuentes, Paul Dade and Billy Smith. Finley claimed them in the Nov. 4 re-entry draft and made no effort to sign them: the union says their chances of signing with orher clubs were damaged, and they want to open up the A's "rights" to other bidders . . . The players association showed its clout this week by making the American League agree to revamp its jerrybuilt 14-team schedule to clear out an alleged 30 or more violations of the labor contract as to day-off requirements, etc. . .

Stuart K. Holcomb, who "did it all" in sports, died yesterday in retirement, at 66, of a heart attack in Venice, Fla. Stu Holcomb came out of Ohio State, captain of the football team in 1931, to be head coach at Muskingum, then Washington & Jefferson, then Miami of Ohio, then assistant to Red Blaik at West Point, then head coach at Purdue (39-42-4) after World War 11; athletic director at Northwestern, 1956-66; general manager of the North American Soccer League's Chicago Mustangs 1966-70; P.R. director (1970) and general manager (1971-73) baseball's Chicago White Sox...Jean Taris, described as France's greatest swimmer, has died at his home in Grasse; heart attack at 68. He broke seven world records, in the 1932 Olympics at Los Angeles, he was beaten by a touch in the 400-meter freestyle, by America's Buster Crabbe...

New jobs: Don Nehlen, who quarter-backed Bowling Green to a 21-24 record in the mid-1950s when Bo Schembechler was an assistant coach there, has joined Schembechler's Michigan staff after head-coaching BGSU to a 53-35.4 log the last nine years; prime mission, developing a Wolverine passing, attack . . . Dennis Ralston, former Wimbledon champion who has captained five U.S. Davis Cup teams, has been hired as director of tennis at the Mission Hills Country Club in Ranche Mirage near Palm Springs, Calif. . . . Walt Bellamy, longtime NBaer including a stint with the Baltimore Bullets, will deploy his 6-foot-10 frame as doorkeeper for the Georgia Senate for the new 40-day legislative session, first black in the job. Two years ago, the doorkeeper was former Atlanta Brave pitcher Pat Jarvis - who last fall was elected sheriff of DeKalb Country, Ga. . . .

Scratch Mike Baker from the Jan. 23 Capital Centre fight card. He ruptured an Achilles tendon and went home to Spartanburg, S.C., to recuperate . . . Rick Monday, the Cub traded to the Dodgers yesterday, joins another good citizen in Steve Garvey - the U.S. Jaycees convention honors the L. A first baseman this weekend in Las Vegas as one of the 10 Outstanding Young Men of America.