Yet Mr. Brooks, on getting a close look at “Trouble With the Curve,” became convinced that the film had Mr. Handfield’s “writing DNA” all over it. According to the complaint and subsequent interviews with Mr. Brooks and his lawyer, Mr. Fox, two prominent film experts — Sheril D. Antonio, of New York University’s film school, and Richard Walter, co-chairman of graduate screenwriting at the University of California, Los Angeles — are prepared to support the case by spotting strong similarities in the projects.

Mr. Brown, who is in his mid-50s and appears to have no produced movie credits before “Trouble,” is represented by Charles Ferraro, a prominent agent at United Talent. So was Mr. Handfield, when “Omaha” was being written — and both Mr. Ferraro and the agency are now named as defendants in the lawsuit.

The suit portrays a tangled series of connections that led to the charges of script theft, including Michele Weisler, a line producer who is represented by the Gersh Agency, which helped Mr. Handfield get “Touchback” made. According to her public interviews, Ms. Weisler worked with Mr. Brown to brush up an old baseball script he had written years ago, then helped get it to Mr. Lorenz. Along the way, she became a producer of “Trouble” — and now joins Mr. Brown, Gersh Agency and one of its agents as defendants in the current suit.

But Matthew T. Kline, a lawyer for Warner and a number of the defendants, including Mr. Brown, fired off a letter on Thursday telling Mr. Fox the allegations of theft and conspiracy were nonsense. The letter also warned those who filed the complaint to agree by next Friday to withdraw it or face potentially crushing legal actions in return.

Mr. Kline attached a draft of a “Trouble With the Curve” script that he said Mr. Brown had optioned to the Bubble Factory, a Hollywood production company, for an initial payment of $2,500 in 1998. The early script, which was markedly similar to the final Eastwood film, was accompanied by an option agreement that ostensibly showed it already existed when Mr. Brooks was still a young ballplayer. (In a separate statement, Mr. Brown called the suit “shameful, reckless and meritless.”)

End of story? Hardly.

“If this is the best they have, they don’t have much,” Mr. Fox said in a phone interview shortly after receiving the Warner blast. He said his investigators had found no evidence that Mr. Brown or anyone else had registered an early script with copyright officials or with the Writers Guild of America, which maintains a widely used service for recording the creation of potential film material.

Mr. Fox said telltales in the supposed 1998 draft actually betray it as something that was “manufactured to provide a defense.”

All will presumably become more clear in court. But likely not until the two sides have played some more hardball.