choroba is always right. Here's more to consider–

use v5.14;
{
    local $_ = "He's out bowling with Fred tonight.";
    s/Fred/Barney/;
    s/with (\w+)/against \U$1\E's team/;
    say;
}
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local and a scope block to protect $_. \U\E to uppercase and end. You could also do raw Perl in the right side of the s///e if you include the e for execute flag. say by itself because $_ is implied.