The San Francisco 49ers should get a big boost for their passing game Sunday when they host the St. Louis Rams, as wide receiver Michael Crabtree is set to make his season debut.

Crabtree was activated from the physically unable to perform list Tuesday. To make room for him on the roster, the 49ers waived cornerback McLeod Bethel-Thompson.

Coach Jim Harbaugh said after the 49ers defeated the Washington Redskins on Monday night that he expects the receiver to play Sunday.

"Crabtree's coming back [this] week, and hopefully, we get a few other guys back," Harbaugh told reporters, according to the Sacramento Bee. "Because we need them all."

Crabtree returned to practice Nov. 5 for the first time since tearing his right Achilles tendon on May 21. By NFL rules, the 49ers had 21 days to decide whether to activate Crabtree to their 53-man roster or shelve him for the season once he returned to practice, making Tuesday the day they had to decide.

The 26-year-old Crabtree, the 10th overall pick in the 2009 draft, had career highs with 85 receptions for 1,105 yards and nine touchdowns for the NFC champions last season. He added 28 receptions for 285 yards and three touchdowns in the playoffs, including a score in the 49ers' Super Bowl loss to the Baltimore Ravens.

Michael Crabtree, the 49ers' leading receiver last season, was activated on Tuesday. Crabtree tore his right Achilles tendon in May. Mike Ehrmann/Getty Images

Crabtree also had five TDs and 30 catches on third-down plays last season -- both stats among the top five in the NFL.

The 49ers have leaned on Anquan Boldin, who leads the team with 53 catches and 724 yards along with five touchdowns, and tight end Vernon Davis, who leads the team in receiving scores (nine) and has 38 receptions for 623 yards.

Injuries to the receiving corps have often been cited for Colin Kaepernick's lackluster passing numbers this season, but Mario Manningham (four catches, 45 yards in Monday night's victory) recently returned to the lineup, and now Crabtree is set to return.

Monday night's performance, in which Kaepernick threw for 235 yards and three touchdowns, was the first time he surpassed 200 yards passing since Oct. 13.

Information from The Associated Press was used in this report.