WR Percy Harvin told reporters that they don’t use the “rebuilding” word around the Vikings training camp, but that doesn’t mean it isn’t taking place. So with rebuilding comes position battles, and there is noteworthy position activity already going on at camp.

WR -- Michael Jenkins vs. Greg Childs. On the first day of practice, WRs Jerome Simpson and Harvin lined up for the first team reps, while Jenkins, who started at wideout before injuring his knee late in the 2011 season, was relegated to second string. Fourth-round draft choice WR Greg Childs, who missed plenty of OTAs with a calf injury, was also on the 2nd string, and coach Leslie Frazier said that he is ready to go. “We think he is 100 percent now,” said Frazier. “He missed a lot in minicamp, so we need him to stay healthy and on the field because we’re counting on him to be in the mix during the regular season.”

RG -- Brandon Fusco vs. Geoff Schwartz. Second-year player Fusco and free agent Schwartz are battling for the starting position, and Fusco received the 1st string reps during the first day of practice. Fusco has known the system longer and it may be his job to lose.

DE/LB -- Everson Griffin vs. himself. Griffin was drafted as a DE three seasons ago. He has been getting reps solely at LB in training camp and coach Leslie Frazier said that is how it will remain. “I do [want him to concentrate on LB],” said Frazier. “I want him to show us that he can play that position. He was our third DE, but we want him to show us that he is now a LB.”

Follow Vikings reporter Joe Oberle on Twitter: @CBSportsNFLMIN.