He will be available tonight at Southend, but will then miss meetings with Shrewsbury and York. Defender Mike Edwards will also miss the York derby as he has five yellow cards to his name.
Alexander has already missed one game this season due to suspension. His first five yellow cards meant he had to sit out of the thrasing by Hartlepool in November.
Neither Lawrie Dudfield or Rodney Rowe are 100% fit but they should be okay to play during his absence. Youngster Gary Bradshaw and Jamaican Theodore Whitmore are also available.
A loan signing has been hinted at by Chairman Adam Pearson. Michael Reddy, Paul Tait and Caleb Folan have joined temporarily earlier in the season to provide attacking cover. There is also Bohemians striker Glen Crowe being linked, but he isn't likely to sign until the summer if at all.