I need help with the baseball file.

If this code also doesn't work, a little more information would be helpful in order to assist further. Basic information, such as how it can be found here, and information on how this code interacts with the file or other VBA code would be beneficial.

Sub BaseballDataTest()
    
    Dim ws As Worksheet
    Dim lastRow As Long
    Dim i As Long
    
    Set ws = ActiveSheet
    
    ' Find last row with data in Column A
    lastRow = ws.Cells(ws.Rows.Count, "A").End(xlUp).Row
    
    If lastRow = 1 And ws.Cells(1, "A").Value = "" Then
        MsgBox "No data found in Column A", vbExclamation
        Exit Sub
    End If
    
    Application.ScreenUpdating = False
    
    For i = 1 To lastRow
        
        ' 1. TRIM all cells in columns A, B, C
        ws.Cells(i, 1).Value = Trim(ws.Cells(i, 1).Value)
        ws.Cells(i, 2).Value = Trim(ws.Cells(i, 2).Value)
        ws.Cells(i, 3).Value = Trim(ws.Cells(i, 3).Value)
        
        ' 2. COLUMN B: Only change if team is NOT Blue Jays, White Sox, or Red Sox
        Dim teamName As String
        teamName = ws.Cells(i, 1).Value
        
        If teamName <> "Blue Jays" And teamName <> "White Sox" And teamName <> "Red Sox" Then
            
            Dim colBValue As String
            colBValue = ws.Cells(i, 2).Value
            
            ' Exact matches (case-sensitive as shown)
            If colBValue = "At Astros" Then
                ws.Cells(i, 2).Value = "@Astros"
            ElseIf colBValue = "Mariners At" Then
                ws.Cells(i, 2).Value = "Vs Mariners"
            End If
            
        End If
        
        ' 3. COLUMN C: Subtract 1 hour from any time value
        If IsDate(ws.Cells(i, 3).Value) Then
            ws.Cells(i, 3).Value = ws.Cells(i, 3).Value - TimeSerial(1, 0, 0)
        End If
        
    Next i
    
    Application.ScreenUpdating = True
    
    MsgBox "Complete! Processed rows 1 through " & lastRow, vbInformation
    
End Sub

What This Code Does

This code will work if your data matches the assumptions above.