The 49ers and Frank Gore have agreed to a three-year extension worth $21M, a source familiar with the deal told ESPN NFL Insider Adam Schefter. The contract contains $13.5M guaranteed, the source said.

The 49ers have activated receiver Michael Crabtree from the physically unable to perform list. The move comes one day after the team notified the NFL that Crabtree caught a couple dozen passes during warm-ups while still on the list. Crabtree hurt his foot during workouts led by quarterback Alex Smith in June during the lockout.

The 49ers notified the NFL on Monday that wide receiver Michael Crabtree caught a couple dozen passes during warm-ups while still on the physically unable to perform list. San Francisco team spokesman Bob Lange said the 49ers immediately reported the "oversight" to the league office after it happened Monday afternoon. It's unclear if the team will be penalized. Crabtree, the 10th overall pick in 2009 NFL Draft out of Texas Tech, has missed his third consecutive preseason, this time while nursing a left foot injury.

49ers left tackle Joe Staley accepted some of the blame for the team's problems on the offensive line in a 30-7 exhibition loss to Houston on Saturday night. "Very disgusted with what we saw on the offensive line," Staley said. "Coach challenged us, he challenged us in the meetings to come out and have a really great week of practice and really great game. We've got to get going. The season is upon us and we've got to play a lot better than that." Staley, a fifth-year pro who received a $42 million, six-year contract extension in June 2009 to lead this line for the long term, was eager to get back on the practice field because he had a "bad feeling" still lingering from the game.

49ers coach Jim Harbaugh says "it's possible" that wide receiver Michael Crabtree could return to practice this week. Crabtree is recovering from a broken foot. According to a source, Crabtree fractured his left foot during a player-run practice in San Jose on June 6. He had surgery on the foot before the start of training camp. He is unlikely to play in San Francisco's preseason finale and his status for Week 1 is undetermined.

49ers running back Frank Gore wants to stay with the team and hopes to get a "fair" deal before the season opener. However, Gore also acknowledged his unresolved contract status is weighing on him and said he wanted to be "treated right." "I just hope everything gets taken care of so I can get my mind right, just ready to play ball," Gore said. He plans to sit out of Monday's scheduled contract talks between San Francisco and his agent, Drew Rosenhaus. Gore, 28, in the final year of a deal that will pay him $4.9 million this season, is hoping for a contract extension before the season opener against Seattle on Sept. 11.

NFL security chief Jeff Miller is confident that Candlestick Park will be a safe venue for fans this season. Miller spent Saturday afternoon meeting with police officers, 49ers security officials and fans a week after two men were shot in a parking lot outside the stadium following San Francisco's 17-3 win over Oakland. He called the violence "unsettling," and something the NFL is taking seriously and plans to "change." "Preseason games across the league generally don't have the same fan base that attends the games throughout the season," Miller said. "I really think a lot of the people who were here last weekend were not the true 49ers fans, they weren't the true Raiders fans. They were people who chose that evening event as their own crime scene, this location as their crime scene. They came here with the intent of maybe drinking a lot and getting involved in things they shouldn't have."

Frank Gore and agent Drew Rosenhaus will meet with the 49ers front office on Tuesday, according to ESPN Insider Adam Schefter. Gore has yet to report and has been vocal about getting a long-term deal.

The 49ers will meet with Frank Gore and his agent, Drew Rosenhaus, on Monday to discuss the running back's desire for a new contract. Little headway has been made on either side as they have publicly traded barbs. Gore, who is in the final year of his contract, has rushed for more than 1,000 yards four times in his six-year career.

Before the 2011 season even begins, the 49ers have vastly improved their coaching situation with Jim Harbaugh replacing Mike Singletary. "I have talked to two different players that each independently told me Singletary was a complete joke as coach, with no attention to detail or any concept of player development," writes Jeff Risdon in his season preview of the 49ers for RealGM. "He often overrode his assistants when they tried to implement wrinkles or use failures as teaching moments, and his insistence on forcing the clearly overmatched Taylor Mays and Chilo Rachal into the lineup damaged the spirit to win." Harbaugh is receiving good marks already "Harbaugh has already earned the respect and trust of the players, particularly the offense."