BLS doesn't automatically center text within the Standing Sheet messages, but when the message size is set to auto, the message box can be resized.
- Open the league
- Select Setup->Standings
- Navigate to the Message tab
- Select the message that you want to modify
- Change the switch that says "Fixed Size" to "Auto"
- Click on the curved arrow near the "Clear Message" button
- It will prompt for "Word Wrap at Column"
- The default value is 75. Set it to something smaller until it fits your tex