Brisbane's win over the Bulldogs has been soured by a knee injury to captain Alex Glenn.
Glenn sustained the injury in the second half and is set to go for scans on a suspected medial cruciate ligament injury.
"He is not real good," Seibold said after the 26-8 win over the Bulldogs.
"It's his MCL (medial cruciate ligament) so he will be in a brace and miss a period of footy. He won't need an operation but he will get a scan tomorrow. They are not concerned about his ACL.
Glenn will likely be able to return before the end of the season.
Winger turned second-rower Corey Oates excelled as Glenn's back-row partner, scoring a try and standing up when the skipper went down to lead the Broncos to their third win of the season.
"I enjoyed what he did tonight. I probably poked Oatesy a couple of weeks ago when I dropped him from the wing," Seibold said.
"It was probably a tough decision, but I thought he was real good in the back row. He ran some really strong lines and defensively he was very good."
Time to retire Alex and let all the young Bronco stars shine !