Tucker also received a two-year contract extension through the 2010 season.

"We are excited to have Mel as our defensive coordinator," coach Romeo Crennel said in a statement. "He has a football plan, life plan, coaches the fundamentals and relates well with the players. I believe he will be successful in this new role."

The 36-year-old Tucker inherits a defense that could look radically different at the start of the 2008 season. The Browns are expected to focus on fixing their porous defense during free agency and in April's draft.

Cleveland's defense was among the NFL's poorest in 2007. The Browns finished the season ranked 30th in overall defense, allowing 5,753 yards — fifth most in club history — and 382 points.

"I'm looking forward to the challenges that lie ahead and I'm confident with hard work we can improve our defense," said Tucker, who left on a family vacation to Mexico on Saturday. "We have a great group of players on this team and my familiarity with them will be an asset."

Grantham's dismissal was a surprise since Cleveland's defense had shown improvement down the stretch, and it was Cleveland's offense, not the defense, which failed to deliver in a crucial loss at Cincinnati on Dec. 23 than ended up costing the Browns a playoff spot.

A Cleveland native, Tucker was an assistant defensive coach at Ohio State from 2001-04 before joining Crennel's staff in Cleveland.

In his first year, the Browns ranked fourth in the league in pass defense. In 2006, Cleveland's secondary was ravaged by injuries but managed to rank 15th despite the loss of starters Gary Baxter and Daylon McCutcheon to injuries.

The Browns had trouble defending the pass this past season, allowing 29 TD passes. But Cleveland's secondary continued to get better under Tucker with rookie cornerback Eric Wright, cornerback Leigh Bodden and safety Sean Jones, in particular, showing future promise.

Also, rookie cornerback Brandon McDonald came on late in the year to contribute.