The central defender only moved to Sheffield United in the summer after his contract expired at Walsall.
The 30-year old defender is also attracting interest from his former team Walsall from where he made 159 appearances for the Saddlers netting 14 goals.
Crewe manager Steve Davis sees Butler as the sort of experienced centre half the team requires after the club lost their opening 5 league games conceding 13 goals in the process.