Zito, the 2002 AL Cy Young Award winner, is 8-6 this season with a 3.29 ERA.
"We're really excited to be associated with a premier pitcher like Barry Zito," Boras told ESPN Insider's Jerry Crasnick. "He's a guy in the prime of his career. He reminds me a lot of Greg Maddux in the early '90s. He's got dominance as a location and control pitcher, and he's durable and consistent at what he does."
Zito's principal appeal lies in his durability. From 2001-05, he led all big leaguers in starts and ranked fourth in innings pitched behind Livan Hernandez, Mark Buehrle and Bartolo Colon. But he is a fly-ball pitcher, meaning a spacious ballpark with a good defensive outfield is crucial to his success.
"He's pretty dependable," an AL personnel man said this spring. "You can count on him for innings. But I don't know if you roll him into Fenway Park or Yankee Stadium and he'll just shut them down. I don't think he's that kind of guy."
Boras said he hasn't spoken with Zito at length about plans for this offseason, when Zito will be one of the top free agent pitchers on the market along with Jason Schmidt.
"We're just working with him physically and mentally about what he does the rest of the season," Boras said. "When it gets around to what Barry does contractually at the end of the season, we'll talk about that then."
Zito is expected to command top dollar, and Boras has a history of landing large contracts for his clients. Last winter, Boras negotiated a five-year, $60 million contract extension for Texas Rangers' pitcher Kevin Millwood and a four-year, $52 million dollar for Johnny Damon with the New York Yankees.
Zito's numbers have cooled since he went 23-5 with a 2.75 ERA in his Cy Young season. In the past three-plus seasons, he has gone 47-42 with a 3.78 ERA.