The Rockies have designated infielder Chris Nelson for assignment, Troy Renck of the Denver Post reports. Nelson was told about the transaction following the Rockies' 3-2 loss to the Diamondbacks on Saturday night. In a corresponding move, the Rockies have called up Nolan Arenado from Triple-A, according to MLB.com's Thomas Harding (Twitter link).
Nelson had a .242/.282/.318 line over 68 PA as the Rockies' regular third baseman this season. The 27-year-old was the ninth overall pick of the 2004 draft and owned a career slash line of .284/.327/.427 in 593 PA from 2010-12. Nelson has played mostly third and second in the majors, and also played shortstop in the minor leagues. The Athletics and Yankees have been interested in Nelson in the past, Renck notes, so it's possible either club could inquire about the infielder during the 10-day designation period.
It was only a matter of time before the Rockies called up Arenado, the club's top prospect and the 52nd-best prospect in the sport according to Baseball America's preseason rankings. Arenado, who recently turned 22, has posted an .818 OPS in five minor league seasons, including a 1.059 OPS over 75 PA at Triple-A this season. His stock somewhat dropped after only an average season at Double-A in 2012 and the Rockies also had questions about Arenado's maturity level, but the third baseman impressed the club both on and off the field during Spring Training. The right-handed hitting Arenado was a second-round pick for the Rockies in the 2009 draft.