Contract negotiations between the Chicago Bears and running back Matt Forte have heated up to the point where the team has extended a contract offer worth $13-14 million guaranteed, a Bears source said Thursday to ESPNChicago.com.

Sources had said Wednesday that the offer approached the neighborhood of $15 million. The potential total value and length of the deal weren't disclosed.

Given recent statements by general manager Jerry Angelo and with the clock ticking on regular-season opener, it appears negotiations are likely coming to a close whether or not Forte agrees to the deal.

The Bears source said the sides are coming into the home stretch and that the organization remains optimistic about consummating the deal before the Sept. 11 start of the regular season.

Escalation of the Forte talks coincide with San Francisco running back Frank Gore's recently signing a three-year, $21 million extension, which included $13.5 million guaranteed. While there is no indication that Gore's deal has affected the talks, the numbers certainly line up.

According to NFL sources, the Bears initially used the six-year, $32 million ($10 million guaranteed) contract signed by Kansas City Chiefs running back Jamaal Charles as the baseline for a potential Forte deal. But it's believed the guaranteed portion of the Bears' actual offer to Forte is worth less than the guarantee received by Gore, which brings up an interesting conundrum for both sides.