sprintf bloginfo odditie

Question

Why the disco funk this is happening I can't quite put my finger on - but I guarantee you it's because I'm probably missing some simple PHP best-practice:

<?php echo '<h3>' . sprintf(__('Welcome to %s', 'roots'), bloginfo('name')) . '</h3>'; ?>

For some reason outputs:

Site Name<h3>Welcome to </h3>

Any light nudges in the right direction would be really appreciated - and maybe a slap on the head once I figure out what's going on ;) Thanks!