Friday night negotations lasted into the wee hours of Saturday before Browns rookie center Alex Mack signed a five-year contract, a source confirmed.
A resident of Santa Barbara, Calif., Mack flew to Cleveland Friday, but didn't put pen to paper until just after 1 a.m. The University of California product was selected 21st overall.
Further terms were not available. Profootballtalk.com reported that Mack will receive a 12.2 percent raise over last year's No. 21 pick, Atlanta Falcons offensive tackle Sam Baker (five years, $13.5 million, $7.8 million guaranteed, according to NFL.com).
Expected to unseat incumbent Hank Fraley for the starting center job, Mack wanted to participate in the Browns' rookie orientation, which began Friday.
A 6-foot-4 and 312-pounder who ran the 40-yard dash in 4.99 seconds, Mack won the 2008 Draddy Award, college football's academic Heisman.
With the full squad reporting date Friday and the first practice Saturday, the Browns will turn their attention to three unsigned second-round selections -- receivers Brian Robiskie of Ohio State and Mohamed Massaquoi of Georgia and linebacker David Veikune of Hawaii. Pro Bowl special teamer Joshua Cribbs and kicker Phil Dawson also hope to renegotiate their deals.