Scotland international Phillips has torn a muscle in his toe joint.
Following a hamstring tear that rules Gary Taylor-Fletcher out for three to four weeks, new Seasiders boss Michael Appleton has problems in attack ahead of Saturday's trip to Bristol City.
He told the Blackpool Gazette: "Matt Phillips has got a slight tear to a joint in his big toe.
"That's been a problem for a couple of weeks and that is a big big disappointment for us.
"He's got a lot of quality and is one of the players who is so important to us."