Based on how effective the 49ers’ passing offense was in 2012, and how it has slumped in 2013, it could be argued that wide receiver Michael Crabtree is the most valuable player in the NFL.

Last season, the 49ers averaged 206 yards passing per game. This year, the average has fallen to 168 yards per game – the worst in the league. In 2012, quarterback Colin Kaepernick averaged 8.3 yards per pass attempt; this season, the number has dropped to 7.1.

The missing element? Crabtree.

In his fourth season in the NFL, Crabtree had a sensational season, with career highs in catches (85), yards (1,105) and touchdowns (9). Whether it was catching passes from Alex Smith in the first half of the season or Kaepernick in the second half, Crabtree was the 49ers’ go-to receiver.

This season, the 49ers have missed his ability to get open, stretch the field and open up other offensive options. Though wideout Anquan Boldin and tight end Vernon Davis have been terrific, the 49ers have missed the Kaepernick-to-Crabtree chemistry that at times was electric last season.

In the final five regular-season games of 2012, Crabtree three times had more than 100 yards receiving and averaged seven receptions. In three postseason games, including the Super Bowl, he had 20 catches for 285 yards and three TDs.

Now, with the 49ers coming off a second straight loss and struggling at 6-4, Crabtree might be ready to play.

The receiver, who tore an Achilles' tendon in practice back in May, has been practicing with the team since early November. And, it was thought he might have been activated for last week’s game in New Orleans, but the 49ers decided to be cautious.

Now, however, the Niners appear on the verge of activating their No. 1 receiver.

San Francisco has an extra day to prepare for its Monday night date with the Redskins, so the timing might be perfect.

When head coach Jim Harbaugh was asked Monday if Crabtree is close to coming back, he told Carl Steward of the Bay Area News Group, “I think so. I think he’s close.”

Harbaugh did not stifle speculation that this could be the week Crabtree gets back on the field in an NFL game.

“We’ll see,” Harbaugh told the media. “A lot of it’s going to depend on him getting out there every day, practicing and see how much of a load he can do.”

In the week leading up to the Saints game, 49ers offensive coordinator Greg Roman said Crabtree was “looking really good.”

Cornerback Carlos Rogers said last week that he didn’t believe Crabtree wasn’t ready for the Saints game because he hadn’t yet started to “talk trash” at him the way he used to. Once Crabtree starts doing that, he’s ready, Rogers said. All he knows is that the team needs Crabtree.

“The sooner he can get out there, I’m sure he’ll be a big help to our offense,” Rogers told the team’s website.