Horne celebrated his testimonial year with Hull FC in 2010
Hull FC say stand-off Richard Horne is likely to miss at least some of the build-up to the 2011 Super League season as he recovers from surgery.
Horne, 28, underwent knee surgery in the close season and could miss pre-season friendlies at Doncaster and Castleford this month.
"He is going to be cutting it fine to make the Castleford trial game," coach Richard Agar told BBC Radio Humberside.
"His rehab has gone really well but we won't take any risks with him."
Horne, who celebrated his testimonial season with the Black and Whites last year, has had repeated injury problems over the past couple of seasons and opportunities to team up with experienced scrum-half Sean Long were limited last year.
"He had some post-season surgery on the knee that was troublesome for him last year and kept him out," Agar added.
"It's now about getting the right amount of work through the knee and building up the muscles around it to make sure it's strong enough not just to last him for the first month of the season but for the full calendar."