Perl - 95 64 bytes

Takes advantage of the fact \u makes the next character printed an uppercase in Perl.
for$c(0..50){$n=1;print map{++$n==27-abs$c-25?"\u$_":$_}a..z,$/}

Thanks to manatwork for saving 31 bytes and fixing it (my previous code did not work.)

Perl - 95 64 bytes

Takes advantage of the fact \u makes the next character printed an uppercase in Perl.

for$c(0..50){$n=1;print map{++$n==27-abs$c-25?"\u$_":$_}a..z,$/}

Thanks to manatwork for saving 31 bytes and fixing it (my previous code did not work.)

Perl - 95 bytes

Takes advantage of the fact \u makes the next character printed an uppercase in Perl.
@a="a".."z";for$c(0..50){$n=1;foreach(@a){$n++;if($n==27-abs($c-25)){print"\u"}print}print"\n"}

Perl - 95 64 bytes

Takes advantage of the fact \u makes the next character printed an uppercase in Perl.
for$c(0..50){$n=1;print map{++$n==27-abs$c-25?"\u$_":$_}a..z,$/}

Thanks to manatwork for saving 31 bytes and fixing it (my previous code did not work.)