Out-of-favour Metcalf was unavailable for Saturday night's 30-12 win over his future club, having missed training this week to finalise his move.
But a serious knee injury to his usual replacement Tanah Boyd looked to have cleared a path for Metcalf to once again become a starting half from next week.
Things might not be so simple, though, after halfback Martin crossed for two tries and played a hand in two others at Jubilee Stadium, where sections of the crowd booed the Dragons at full-time.
Saints gave up three restarts and a penalty ahead of Martin's first try, with the halfback dummying past Hayden Buchanan to the tryline.
He had a second try 10 minutes after the break, shrugging out of Clint Gutherson's tackle and then bolting past Josh Kerr.
Martin combined with Chanel Harris-Tavita ahead of Alofiana Khan-Pereira's second try, with the five-eighth throwing a great ball on the left to confirm his winger's double.
Dallin Watene-Zelezniak sealed the win, and his own double, picking off a Luciano Leilua pass and running 20 metres to score untouched in the last 10 minutes.
The second-placed Warriors' sixth straight win came without State of Origin stars Kurt Capewell and Mitch Barnett, and despite mid-game injuries to Roger Tuivasa-Sheck (knee) and Eddie Ieremia-Toeava (head knock).
The twin blows meant Jackson Ford switched to second row in his first game since being snubbed from NSW Origin selection.
After losing Jaydn Su'A (calf) at captain's run, the Dragons had to contend without his replacement centre Buchanan, who went down with a shoulder injury early in the first half.Â
Damien Cook limped off in the final minutes with an apparent ankle issue
The Warriors cashed in; four of their six tries came against a makeshift right edge that had Gutherson defending at centre.
Saints were more competitive than in their last outing at Kogarah, when they were roundly booed from the field in a 32-0 round-five loss.
They managed the first try of the game thanks to a flat pass from Dan Atkinson to Hamish Stewart, who slipped a one-handed offload to Setu Tu.
But red-zone execution remains a big issue, and the Dragons are now on the outright second-longest losing streak of the NRL era.
They are behind only Newcastle's dismal 19-game slide that ended in early 2017.
