Chargers guard Kris Dielman is expected to officially announce his retirement on Thursday. Dielman, a four-time All-Pro, was an anchor of the San Diego's line but finished the 2011 season on injured reserve because of a concussion.

The Chargers plan to release longtime defensive end Luis Castillo rather than pay him a $1 million roster bonus in March, according to a source. The team has spoken to his agent and he will seek a job elsewhere, but San Diego also made it clear that they want Castillo back. Castillo, 28, broke his left leg in the season opener on Sept. 11 and the Chargers kept him on the active roster in the hope he'd be healed toward the end of the season. However, he was ultimately placed him on injured reserve in December.

About to enter his 15th season, the Chargers are expected to bring Takeo Spikes back for another year. The soon-to-be 36-year-old is due $2.875 million in 2012. "Save yourself some time and ink," San Diego general manager A.J. Smith said. "Takeo Spikes isn't going anywhere. He will be a Charger this season. We are very fortunate to have him as part of this situation. He's a true professional in every sense of the word and brings a veteran presence in our locker room."

The Chargers want to retain Vincent Jackson, but they are reluctant to franchise the wide receiver. It would cost San Diego nearly $13.7 million to place the franchise tag on Jackson. Otherwise, he will become an unrestricted free agent March 13, allowing him to negotiate and sign with another team. While retaining Jackson is considered a top priority for general manager A.J. Smith, sources said Smith is "extremely uncomfortable" allocating that much money to a one-year guaranteed deal.

Chargers center Nick Hardwick says that he plans to play in 2012. The 30-year-old, who is scheduled to be a free agent, raised questions about his future late in the season when he said he was considering retirement. "I guess we'll just have to see where that goes," he said. "I obviously have a lot of best friends in that building, including on the coaching staff. I'd certainly like (to stay). I hope I'm in their plans. If not, we're ready to go on." Hardwick, who was a Pro Bowl selection in 2006, said his commitment to playing is "full throttle."

The San Diego Union-Tribune reports that the Chargers will almost certainly allow Vincent Jackson to hit the free agent market this offseason. There will be a number of wide receivers on the market -- including Wes Welker, DeSean Jackson and Reggie Wayne. San Diego will surely bid for Jackson, but they aren't concerned about him hitting the open market.

Vincent Jackson would be the biggest name on a long list of wide receivers to hit the free agent market next month. However, the Chargers hope to keep him from hitting the open market at all. "I'm told by people in San Diego they're going to do everything in their power to sign him, but this is going to be expensive," NFL Network's Michael Lombardi told "NFL Total Access" on Thursday. "There are a lot of teams that need an outside, big-play receiver." Jackson has maintained his preference is to stay in San Diego despite a relationship with the front office that has been acrimonious in the past. He earned $11.4 million during the 2011 season under the franchise tag, a figure that is expected to increase to $13.7 million this offseason.