The Washington Nationals yesterday signed 15-year veteran shortstop Royce Clayton to a minor league contract and told him he would have an opportunity to compete for the team's starting job this spring -- a clear signal to incumbent Cristian Guzman that, big contract or not, his place in the starting lineup is not guaranteed. "We're not going to sit back and watch Cristian Guzman have another year like he did last year," General Manager Jim Bowden said, referring to Guzman's .219 batting average and 31 RBI in 2005. "This [signing] gives us a viable option to go to in the event we don't see improvement from Guzman."