Richmond star Dustin Martin is in doubt for Saturday's clash with Sydney at the MCG after leaving training early on Thursday.

Martin pulled up holding his back and left the Tigers' main session early, and headed straight for the tunnel and missing the rest of the session.

The club is confident Martin will take the field on Saturday, and has otherwise named an unchanged line-up for the first time this year.

The Swans present a challenge for the fourth-placed Tigers, who could cement themselves in the top four with a win against an in-form Sydney outfit.

Martin has played every game so far in 2017, and even played with a "minor" fracture to his cheekbone in round three against West Coast after suffering the injury against Collingwood the week before.

The 25-year-old has been one of the league's best this season, averaging 29.9 disposals a game (14th in the competition), 14.5 contested possessions (6th), 6.7 clearances (9th) and 6.1 inside 50s (1st).