Bush gets a four-year contract worth up to $14 million, including $7 million in guaranteed money, according to a source.
"There's only so many times a man that has done everything he's been asked to do can be disrespected!" read a post on Forte's Twitter account early Thursday afternoon. "Guess the GOOD GUYS do finish last ..."
Later in the day, Forte attempted to more succinctly direct his ire with the following two posts on his Twitter account: "for the record I'm not mad at the signing of another running back. This is 4th time that's happened. I embrace competition as well as help." He added, "But as for not taking care of ur own and undervaluing a player under his market value is another story! #twitterrant"
Forte recently was designated the club's franchise player as the sides work to come to a long-term deal. The signing of Bush could be viewed as somewhat of an insurance policy for the Bears in the event Forte decides to hold out. The sides have until July 16 to come to an agreement on a multiyear extension. After that date, Forte must play under the tag, which comes with a salary of $7.74 million.
"Since drafting Matt in 2008, the Bears have signed Kevin Jones, Chester Taylor and Marion Barber, all ostensibly to serve as Matt's backup," Forte's agent Adisa Bakari said. "To sign yet another running back, prior to completing a contract with Matt, suggests disregard for Matt and his contributions to the Bears."
Forte has said in the past that he would be "hard to find" if the Bears tagged him, but the Bears have been adamant in expressing a desire for the sides to come to a long-term agreement.
"Matt is going to play his football for the Chicago Bears, you start with that," coach Lovie Smith said at the NFL scouting combine. "In time, hopefully, we can get an agreement in place that suits Matt, and we feel comfortable with. I think it's just a matter of time. That will happen eventually."
Bush empathizes with Forte and said he figured his new teammate will hold out.
"I can understand where the guy's coming from," Bush said. "
Everything they've asked for, he's done. It's one of those things where you want to be rewarded for your success. I understand, but that has nothing to do with me. It'll be great working with him."
What the Bush deal most likely signals is the end for Barber, a 2011 free-agent acquisition, who carries a cap charge of $2.25 million into the 2012 season.
Releasing Barber would represent a cap savings of $2 million.
A fourth-round pick of the Raiders in 2007, Bush ran the ball 632 times for 2,642 yards and 21 touchdowns over four seasons, despite missing his rookie year because of a broken leg suffered in college at Louisville. Bush, 27, is coming off his best season as a pro, a campaign in which he gained 977 yards on 256 attempts in addition to scoring seven TDs.
Bush had 43 carries in Oakland's first six games for just 138 yards and a 3.2 average per carry. But after Darren McFadden was injured, Bush rushed for 839 yards on 213 attempts. He had 418 receiving yards and one touchdown through the air as well.
Bush carried 24 times for 69 yards and a touchdown in Oakland's Week 12 victory over Chicago, which kick-started the Bears' five-game slide at the end of 2011.
The acquisition of Bush marks the Bears' third attempt in as many years to bring in a capable backup for Forte. The Bears paid Taylor $7 million guaranteed in 2010, before releasing him on Sept. 3 after the veteran averaged just 2.4 yards on 112 carries.
The Bears didn't fare much better with Barber, who was signed on Aug. 1 to a two-year contract that included a $500,000 signing bonus and base salaries of $2 million and $1.9 million in 2011 and 2012, in addition to a $100,000 workout bonus. Barber rushed for 422 yards and six touchdowns last season, but missed the first three games because of a calf injury.
Barber missed the final two games with a calf injury as well.
His most memorable moments came in a 13-10 overtime loss in Week 14 at Denver, a game in which two Barber mistakes (falling out of bounds to stop the clock just after the two-minute warning with his team leading 10-3, and fumbling in overtime) led to the Broncos scoring 10 unanswered points in the last 2:08 to tie the game with three seconds remaining in regulation, before eventually winning on a 51-yard field goal by Matt Prater in overtime.
The Bears haven't made any announcement regarding Barber's future. But it's highly unlikely they will carry Bush, Forte, Barber and Kahlil Bell -- recently tendered a qualifying offer worth $1.26 million -- on the roster.
Bush started in 19 games over four seasons with the Raiders, which likely gives the Bears confidence in his ability to fill in for Forte.
"I was kind of surprised," Bush said. "Every meeting that I went to, they were saying they wanted to do a two-back system. I can't argue with that.
On Twitter, former Bears tight end Greg Olsen weighed in on the acquisition of Bush.
"If u have a stud 3 down guy like @MattForte 22 why keep paying backups big $ every yr?" Olsen wrote. "Crazy !! Matt deserves better."
Michael C. Wright covers the Bears for ESPNChicago.com and ESPN 1000.