Essendon small forward Travis Colyer is expected to be sidelined for up to three weeks after developing inflammation in the sesamoid bone in his right foot.
Colyer, who averaged 16.7 touches and kicked 12 goals in 2017, will be in a moonboot until his foot has fully recovered and is able resume his training program.
"Trav had some sesamoid pain," Essendon High Performance Manager Justin Crow told essendonfc.com.au.
"The sesamoids are a couple of little bones under your foot that can become painful.
"We want to settle that down, so we've got Trav in a boot.
"He'll stay in the boot for three weeks now and he'll come out of that hopefully with the sesamoid settled and then he'll build back up again."
The news is better for key defender Michael Hurley however, who is recovering strongly from his wrist and hip surgery at the end of last season.
"Michael Hurley has had a good pre-season," Crow said.
"He'll be in some match play on Friday and we're really happy with how 'Hurls' is going."
Crow also provided an update on recovering duo David Myers and Matthew Leunberger, and was optimistic about the pair's conditions.
"We had that (finger) operated on and that hasn't affected David's pre-season at all," Crow added.
"He's actually got in the majority of training both pre- and post-Christmas and he's in a really good place.
"Leuenberger had that shoulder operation and he's just come up to four months post-surgery now.
"He's worked through contact progressions in competitive training drills and elements of match play so he's progressing really nicely and has a good training base."
Josh Green, Jackson Merrett and Ben McNiece have all been able to build their fitness bases after various injuries, whilst Aaron Francis has experienced a minor setback with a hip flexor concern.
