Hampered by recurring soreness in his right knee -- a byproduct of two significant injuries in the same area last year -- Tinoisamoa missed practice on Wednesday, was limited Thursday and not on the field Friday.
"I did [expect Tinoisamoa to be available] earlier [in the week], but things changed a little bit," Bears coach Lovie Smith said. "He didn't come around as much as we wanted him to."
Smith expressed concern Thursday about the linebacker's availability in the minutes following the club's indoor workout at the Walter Payton Center. The club practiced indoors on Wednesday and Thursday before heading outside for the final day of preparation.
"Whenever you have a guy who isn't able to practice on Thursday, there's some concern," Smith said.
"I've been getting the reps in practice," Roach said. "You don't want there to be any let-off just because somebody new comes in."
Roach and Tinoisamoa were embroiled in a hotly contested battle for the starting job during training camp, but a minor knee surgery in August knocked Roach out of the running.
"With a 53-man roster, we feel like we're pretty deep," Smith said. "Nick has started a lot of games for us, so that lightens the load a little bit with Pisa missing. Hopefully we won't miss a beat."
Tinoisamoa, meanwhile, has also been a victim of various knee injuries. An eighth-year veteran, Tinoisamoa played in just two games last season -- his first with the Bears -- before going on injured reserve on Dec. 1 because of knee problems.
Michael C. Wright covers the Bears for ESPNChicago.com and ESPN 1000.