The actor will reprise his role as the CSI's ex-husband in tonight's episode, which airs at 9/8c on CBS.
"There's certainly still something there for Russ, but there is a wall that needs to be scaled first," he told TV Line. "I don't know if Russ gets there, but we're teasing it."
He revealed that the FBI agent will assist Jo when her daughter witnesses a brutal murder in Penn Station.
"The murder dovetails certain characters that the FBI has on their database," he explained. "Jo and the NYPD access info through Russ, and he helps a little bit, just as he did the first time around."
The actor also refused to rule out a third appearance as Russ in the future.
"You've seen me a second time, so maybe you'll see me a third," he suggested. "The [writers] like [Russ and Jo] together, I know that. That's why they brought me back."
CSI: NY producer Pam Veasey previously suggested that Russ and Jo could become involved in a love triangle with Mac (Gary Sinise).
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