The Bears had a solid one-two punch with Johnson and McKie opening up running lanes for Thomas Jones a season ago. The duo had expected to do the same for Jones and Cedric Benson, but there is suddenly little depth at fullback.
Keith (Thump) Belton is currently the only healthy option at the position. The undrafted free agent out of Syracuse spent the bulk of his rookie season on the Lions practice squad. Primarily a lead blocker for the Orangemen, he earned the nickname "Thump" for a reason. He's capable of taking on linebackers and safeties in Ron Turner's run oriented offense.
Chances are Johnson will be ready when the season starts, but after working during mini-camp he sat in June because of soreness the surgically repaired foot.
Of the fullbacks on the squad, McKie brings the most versatility being able to catch and run with the ball. Johnson has the ability to catch the ball, while in college Belton had just 7 receptions in two years at Syracuse.
There are similar questions at tight end.
The job appeared to be Desmond Clark's for the taking, but even before he went down with an ankle sprain, Lovie Smith knew there were limitations to what the seven-year veteran can do.
"Desmond Clark can be a very good tight end," Smith said. "We don't have an all-pro at that position. But I think we can win with a very good tight end. We don't need an all-pro yet."
Clark has never turned out to be the pass-catching threat the Bears hoped they were getting. He has been an inconsistent catcher at best who lacks the quickness and speed to get separation. After catching 42 balls in his first season with the Bears that number dropped to 24 last year.
The Bears' problem is that they've never had anyone any better at the position.
Dustin Lyman is the longest tenured receiving target on the roster and will take the majority of the first team reps until Clark returns. He has just 37 career receptions and has had problems staying healthy over the course of his career.
John Gilmore is bigger and more physical than the other two but isn't a threat as a receiver.
Ron Johnson is a converted receiver that has been working with the tight ends during the off-season. He could be the best option in the passing game, but at 233 pounds will not be able to handle blocking responsibilities, which will limit his time on the field.
At this point, there is little the Bears can do at either position beside go with what they have on the roster. It could be a matter of putting players in positions they're not accustomed to until the injured get healthy.