WWE fans noticed to huge names were absent from SmackDown Live this week, that being Daniel Bryan and Sheamus.

Bryan hasn't been seen inside a WWE ring since he lost the WWE Championship at WrestleMania 35 to Kofi Kingston.

Sheamus has been seen since The Showcase of Immortals, but he surprisingly wasn't with his The Bar tag team partner Cesaro this week on WWE's blue brand show.

So why weren't they on SmackDown? Neither of them had been moved to Monday Night Raw as part of the Superstar Shake-up. They were both actually taking time off due to injuries.

PWInsider has reported that Bryan wasn't featured on WWE TV this week as he's dealing with an injury coming out of WrestleMania. However, the nature of the situation has been closely guarded.

Sheamus, meanwhile, is also taking time off with an injury, which is why he didn't appear alongside Cesaro on this week's SmackDown.

The Wrestling Observer Newsletter, via Ringside News, has reported that The Celtic Warrior is currently dealing with a concussion, so he won't be able to return until he clears concussion protocol.

Both former WWE Champions have had serious injuries in the past which have put their careers in jeopardy, Bryan with his concussions and Sheamus with his spinal stenosis, so it's easy to understand why some fans might be concerned with their absence.

Bryan has an extensive history of concussions, and while we don't know if he's actually suffered another one, the fact that the nature of his injury is being treated as a need-to-know business isn't a good sign.

Both Bryan and Sheamus are two of WWE best workers in the ring and it would be a real shame if they were forced out of action for some time.

All fans will be keeping their fingers crossed that these injuries are ones which both superstars are able to bounce back from and return to the ring very quickly.

There are some great feuds for Bryan on SmackDown following the Superstar Shake-up, as he could have great clashes in the ring against the likes of Roman Reigns, Elias, Finn Balor, and Lars Sullivan.

As for Sheamus, when he returns and teams with Cesaro as The Bar once more, they could feud against The Hardy Boyz for the SmackDown Tag Team titles, or against the blue brand's newest tag team thanks to the Superstar Shake-up, Heavy Machinery.