use strict;
use warnings;
use Data::Dumper;

my $string = "QB Carson Palmer RB Chris Ivory RB Eddie Lacy WR A.J. Green WR John Brown WR Davante Adams TE Martellus Bennett FLEX Jeremy Hill DST Panthers";

my @words = split ' ',$string;
my $i = 0;
while ($i <= $#words) {
  if ($words[$i] =~ m/^[A-Z]{2,4}$/) {
    $words[$i++] .= ' ->';
  } else {
    $words[$i-1] .= ' ' . splice @words,$i,1
  }
}
print Dumper(\@words);