Both players were running at full pace from opposite directions in a bid to catch Cooper Connolly's skied shot when they collided in Friday night's BBL clash with the Perth Scorchers at Optus Stadium.
Sams, who was running in from the boundary, appeared to be knocked out cold in the horrific clash of heads, with the 32-year-old laying prone on his back.
Bancroft, who was running with the flight of the ball, did not lose consciousness but was clearly hurt.
Sams was taken off by medi-cab after the collision. (Richard Wainwright/AAP PHOTOS)
Thunder players rushed in as soon as the incident occurred, with the two Scorchers batters stopping their running between the wickets out of respect for the injuries.
After some five minutes of treatment, a groggy Bancroft was able to walk off the field with the help of a trainer, blood streaming from his nose as he left the field.
Sams was treated by his team's medical staff as well as an ambulance crew before being taken off on a medi-cab.
The Thunder later confirmed that both players had been concussed and were taken to hospital for further assessment, with concerns about possible fractures.
Ollie Davies and 20-year-old debutant Hugh Weibgen were approved as the duo's concussion replacements by the match referee.
Davies wasn't initially picked for the match because of illness, but the Thunder were left with little choice after losing two players at once to concussion.
Bancroft (right) and Sams were floored by the collision. (Richard Wainwright/AAP PHOTOS)
The Scorchers were 4-126 after 15.2 overs when play was halted while Bancroft and Sams were attended to.
Perth finished their innings at 4-177, with opener Finn Allen (68 off 31 balls) and Cooper Connolly (43no off 31 balls) the major contributors.
The Scorchers looked on track for a score in the vicinity of 200 after moving to 2-110 after 12 overs.
Bancroft leaves the field injured and bloodied. (Richard Wainwright/AAP PHOTOS)
Allen was on 31 when Thunder wicketkeeper Sam Billings dropped a tough skied catch running with the flight of the ball.
The Kiwi opener went on to crack six fours and five sixes during his dazzling knock, setting the Scorchers the perfect platform to launch from.
Allen helped take 22 runs off Sherfane Rutherford's one and only over.
But a superb effort from Thunder spinner Chris Green (3-20 off four overs) halted Perth's momentum as the home side lost 3-8 in a mid-innings slump.
Allen's dismissal at the hands of Green was crucial as the Thunder slowed Perth's run rate.
Connolly tried his best to get the Scorchers' innings going again, and Nick Hobson chipped in with 21no off 17 balls, but they both lacked the destructive aura of Allen.
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