Parmele, who rushed for 143 yards on 40 carries this season while seeing an expanded role due to Maurice Jones-Drew's midseason foot injury, hurt his groin during Sunday's 24-19 win over Tennessee. He had 45 yards on eight attempts before exiting.
Middleton sustained a concussion in Jacksonville's 43-37 overtime loss at Houston on Nov. 18 and sat out last week's contest as a result. The fourth- year pro had recorded 20 tackles and made three starts in 10 games prior to the injury.
The Jaguars also released wide receiver Micheal Spurlock and veteran safety Chris Harris while signing cornerback Antwaun Molden and wide receiver/return specialist Quan Cosby. In addition, the team inked running back Jordan Todman off the Minnesota Vikings' practice squad and rookie wide receiver Toney Clemons off the practice squad of the Pittsburgh Steelers.
Molden owns four years of NFL experience with Houston and New England and compiled 36 tackles and two interceptions while playing all 16 games with the Patriots in 2011. He signed with the New York Giants during the offseason, but did not make the team's final roster.
Cosby has previously played for Cincinnati, Denver and Indianapolis during a four-year career spent primarily as a return man. The 29-year-old owns a 10.0 overall average on 97 punt returns and a 22.4 average on 33 kickoff runbacks.
Spurlock appeared in six games with Jacksonville after being released by San Diego in October and had 14 receptions totaling 121 yards with one touchdown as a Jaguar.
