The Gunners captain has struggled for game time this season, with just three Premier League starts to his name, but his fellow defender insists the skipper's impact is vast.
Vermaelen has started just three Premier League matches in the current campaign, with Mertesacker and France international Laurent Koscielny currently Arsene Wenger's first-choice pairing at the heart of defense.
Vermaelen has reportedly shown an excellent attitude in training as he patiently waits for his chance, and Mertesacker has hailed his contribution off the pitch.
"Laurent, Thomas and myself I think we push each other to good form," the German told Arsenal Magazine. "At the moment, it is linked to me and Laurent, but I have to say that Thomas is a role model for everyone here — not just because he is the skipper, but in the way he communicates, handles his situation when he's not playing.
"People always speak about those who are in the team, but you have to mention the players who are not involved in the starting XI, but who have the right influence on the rest of the team."
Mertesacker noted that the players are all comfortable playing alongside each other for Wenger's table-toppers.
"We are good center backs," he added. "It takes some time to get used to each other on the pitch, and feel comfortable with the situation on the pitch. At the moment we know each other well, and how we behave on the pitch. We know how to cover each other, we know how our partner will handle the key moments."