Connor did not play against Atlanta because of a stinger suffered the previous week and was expected to miss two games, although a checkup on Monday went well. Lemon suffered a hamstring injury against Atlanta and will not play this week.
Ernie Sims was signed two weeks ago and started in place of Connor. Alex Albright would be a backup inside linebacker candidate as well.
Guyton was with Miami in training camp. He spent the 2008-11 seasons with New England. Poppinga is an eight-year veteran, spending time with Green Bay and St. Louis.
“We absolutely have to work around (the injuries),” coach Jason Garrett said. “Albright is a good candidate because he’s a smart guy and he can play both inside and outside. But we will be thin there if both those guys are hurt.”