JACK Gunston has strained the medial collateral ligament in his left knee, leaving his finals campaign in limbo, Brisbane has confirmed.

In other injury news for the Lions, veteran defender Daniel Rich has suffered another hamstring injury and will be unavailable for up to four weeks.

Gunston hobbled off the Gabba just before half-time in Saturday's six-point win over Adelaide after having his knee buckle in a tackle.

Scans on Monday confirmed what coach Chris Fagan suspected in his post-match press conference, ruling the three-time premiership Hawk out for at least the remaining two home and away matches.

Brisbane says it will further assess Gunston's injury to determine the "best course of action for a possible return during the finals".

The key forward has kicked 22 goals from 17 matches this season.

Rich also went for scans on Monday after leaving the field in the early stages of Saturday's VFL match.

It's the second time in recent weeks the 33-year-old has strained his hamstring, continuing a frustrating season that has not quite got on track.