Dolphins add 2 WRs, also waive 2

DAVIE, Fla. -- Receiver Julius Pruitt has re-signed with the Miami Dolphins, who cut him near the end of training camp last year, while receiver Armon Binns, who was a leading candidate to be the team's fourth receiver this season, was placed on the waived-injured list after suffering a knee injury earlier this week.

Binns reportedly tore the ACL and MCL in one of his knees Sunday. Receiver Jasper Collins also was waived-injured Wednesday.

The Dolphins can place Binns and Collins on injured reserve if they clear waivers.

Pruitt played nine games with Miami in 2011, mostly on special teams.

The Dolphins also signed receiver Keenan Davis, an undrafted rookie free-agent receiver from Iowa. Davis played for Dolphins receivers coach Ken O'Keefe at Iowa, where the assistant was the Hawkeyes' offensive coordinator. Davis signed with the Cleveland Browns after April's draft but was recently released.

A source told ESPN.com's James Walker that the Dolphins also tried out veteran receiver Laurent Robinson, who was released by the Jaguars after suffering four concussions in his first season with the team, on Tuesday.

Mike Wallace, Brian Hartline and Brandon Gibson are firmly entrenched at the top three spots on the Dolphins' receiver depth chart.

The Dolphins play their first preseason game Sunday when they face the Dallas Cowboys in the Hall of Fame Game in Canton, Ohio.

Information from The Associated Press was used in this report.