Fine. If Detective Bobby Simone isn't going to get married, have babies, heal that wounded macho heart of his and keep partner Andy Sipowicz on the straight and narrow, he may as well just check out.

Which, of course, is what he's doing. Jimmy Smits, of the smoldering eyes, fatherly air and sensual rear end familiar to viewers of "NYPD Blue," has announced he will be leaving the hit ABC police drama at the end of this season.

A loss for the show. A risk for the actor. A bummer any way you look at it.

"My career aspirations as an actor have always been driven foremost by the creative desire to be versatile," Smits said yesterday in a written statement. "I have and will continue to vigorously pursue opportunities in all mediums." He declined to be interviewed yesterday by The Washington Post.

Steven Bochco, the show's creator, said Smits informed him of his decision several weeks ago, but some ABC executives said they learned of Smits's departure only in the past couple of days. The network has quickly scrambled to persuade Smits to stay at ABC, perhaps at a new show. "We're looking to have him come back to the network if he wants to." said Steve Tao, ABC's vice president for drama programming. "Our discussions are in the very preliminary stages," he added. Bochco said he would write an original show for Smits, if asked, "in a heartbeat."

Smits, 42, becomes the second lead actor to see his star rise on the hard-hitting, often controversial show and then leave; David Caruso, whom Smits replaced in 1994, quit after the series launched his career in its first season. Smits, however, is an accomplished actor -- he won an Emmy in 1990 for his work on the 1980s series "L.A. Law" -- and is leaving at the close of his four-year contract.

The show's producers stressed that they respected the actor's decision. "I know that when Jimmy makes a decision like this, it's never a ploy with him. It's usually a really thoughtful decision on his part," said Bochco in an interview. "His deal is up, and I think he just saw that as an opportunity to expand his horizons."

While replacing Smits may be difficult, the guts of the drama remains in actor Dennis Franz, who plays Smits's partner, Andy Sipowicz, an overweight, balding, vaguely racist recovering alcoholic. The series began the season focusing on Simone and his relationship with another detective, Diane, played by Kim Delaney, who finally agreed to marry him. But that plot line quickly took a back seat to other conflicts, and the show currently focuses on Sipowicz's most recent trauma, a battle with prostate cancer.

Franz has won repeated Emmys for his portrayal of Sipowicz and has confirmed that he will continue to play the role next season. Smits had given no hint that he might not do the same at a party thrown for television critics on the set in January. At that event, the show's writer, David Milch, lit candles on a cake to mark the show's 100th episode as a shy Smits praised his colleagues, expressed gratitude to the show and then broke into a goofy rendition of the song "We're Having a Party."

Trained at Brooklyn College and Cornell University, the textbook tall, dark and handsome Latino actor began his acting career in New York theater and got his first big break in television with the role of lawyer Victor Sifuentes on the Bochco series "L.A. Law." After that series ended, Smits landed some roles in TV miniseries and small feature films. His most prominent film role was in the 1995 Hispanic-cast drama "My Family."

It is not clear whether Smits intends to try to pursue a career in feature films, as his predecessor Caruso did (without success -- he is back on prime time as moralizing district attorney "Michael Hayes"). Those connected to the series said it seemed Smits was leaving to look for a new creative challenge, not because of any particular dissatisfaction over his character or salary.

Smits said he would return to the show in the fall for several episodes to help "bring a resolution" to his Detective Simone character.

While still critically acclaimed, "NYPD Blue" has slipped in the ratings in the last year and is ranked 17th among prime-time shows, losing to the Tuesday edition of "Dateline NBC," its direct competition. But Bochco rejected the notion that the show was ready to wind down after a successful run. "I think this show has extraordinary creative energy and freshness. No one's phoning it in," he said.

As for how he will replace Simone, Bochco said: "You don't try to. It's impossible. What you try to do is come up with some sort of fresh, different addition. We don't have a clear, specific creative vision yet; we're too busy finishing this season. As soon as it's done, we'll sit down and look at that." CAPTION: Jimmy Smits has decided to leave ABC's hit police drama at the end of this season.(Photo ran in an earlier edition)