Center Travis Frederick, the first pick of the Dallas Cowboys in the 2013 NFL Draft, was the last to sign a contract.Frederick agreed to a four-year contract with the Cowboys on Tuesday. Financial details were not disclosed, but a source said it was for a total of about $6.8 million. Of that total, said the source, about $5.5 million was in guaranteed money, including a $3.4 million signing bonus.He was the 31st pick of the first round and is expected to start immediately at center. He took all the snaps with the first team in organized team activities and minicamp.Frederick’s signing completes the seven-member draft class and marks the earliest signing of an entire class by the Cowboys in years. Training camp begins July 19.Spencer updateEver since the Cowboys placed the franchise tag on defensive end Anthony Spencer in March, it was a long shot that they would be able to sign him to a long-term deal.The depressed free-agent market has driven down prices and Spencer, who said he wants to stay in Dallas, had no intention of taking a below-market deal when he was already guaranteed $10.6 million this year with the franchise tag.Not surprisingly, the two sides decided to end the impasse and just concentrate on the 2013 season with no further talks.“Both sides are happy with the one-year deal,” Spencer’s agent, Jordan Woy, said Tuesday. “We tried hard, but could not work out a deal. We have a very positive relationship with the Cowboys. Anthony is happy and he will play to the best of his ability again this season”The Cowboys have until July 15 to work out a long-term deal with Spencer, per league rules.Woy said no one has broken off talks, but he acknowledged that they aren’t talking and will probably just concentrate on the upcoming season.“Obviously, we have to take a look at what people signed for and what they’ll make going forward,” Cowboys vice president Stephen Jones said two weeks ago. “There’s some good football players that, what they got paid, might affect what we want to pay Anthony going forward. “There’s nothing here that’s not on the up and up and friendly. If it works out, it works out. We’d love to have Spencer here, but we also understand it has to work for him, too.” Spencer will most certainly get a long-term deal next spring, in Dallas or elsewhere. The Cowboys are unlikely to put a franchise tag on him for a third consecutive season because that would require, by league rules, paying him the quarterback franchise tender, guaranteeing him in excess of $15 million in 2014.