Patrick Willis is calling time on his NFL career.

Yahoo! Sports' Rand Getlin reports that the San Francisco 49ers linebacker is expected to announce his retirement as soon as Monday afternoon.

Willis, 30, appeared in only six games last season due to a nagging toe injury that required surgery. He missed five games the previous year with a broken hand and a groin problem.

Taken 11th overall in the 2007 NFL Draft out of Ole Miss, Willis was a force out of the gate, winning Defensive Rookie of the Year that season. The native of Bruceton, Tennessee was a seven-time Pro Bowler over his eight-year career, missing out last season.

Willis reached the Super Bowl in 2013 with the Niners, but came up short against the Baltimore Ravens.

The 49ers could be losing another defensive stalwart to retirement in Justin Smith.

It was reported Monday that Smith was also heading for retirement but the veteran defensive end told the Sacramento Bee that his decision isn't 100 percent yet.

The 35-year-old was drafted fourth overall in 2001 and has spent his career split between the Cincinnati Bengals and 49ers.

Smith is coming off a 43 tackle, five sack season, his 14th in the NFL.