Why do you need to?

$game{'board'}{'stat'} =
    "$playerin submits"
    . " $game{'board'}{'proposedworduser'}"
    . "  $game{'board'}{'proposedscore'} points";

# or

$game{'board'}{'stat'} = join( " ",
    $playerin,
    "submits",
    $game{'board'}{'proposedworduser'},
    " ",
    $game{'board'}{'proposedscore'}
    "points"
);

# or

$game{'board'}{'stat'} = sprintf(
    "%s submits %s  %s points",
    $playerin,
    $game{'board'}{'proposedworduser'},
    $game{'board'}{'proposedscore'}
);
[download]

TMTOWTDI, as always.