The Cleveland Browns opened up a mandatory three-day mini-camp today, and six players, including four unsigned restricted free agents, are not in attendance, Mary Kay Cabot of the Cleveland Plain-Dealer reports.

Among the missing are restricted free agents Lawrence Vickers, linebackers Matt Roth and D'Qwell Jackson, and safety Abe Elam. Roth, Jackson, and Elam's absences are not a surprise, but Vickers appeared at the team's voluntary Organized Team Activity sessions earlier this week, and told reporters that he planned on attending the mini-camp.

Running back Jerome Harrison, also an unsigned restricted free agent, is attending, while Peyton Hillis, acquired from the Denver Broncos in the Brady Quinn trade, is not in attendance. Cabot notes that Hillis was battling an undisclosed illness earlier this week.

Veteran kicker Phil Dawson is also a no-show, which isn't a surprise as he's unhappy with his current contract, and has avoided the team's off-season workout program. Dawson faces daily fines in the amount of $9,000 for not showing up for mini-camp.