 Horwood made his Tranmere Rovers debut in the opening game, where he started the whole game, in a 3–1 loss against Walsall.It wasn't until on 1 September 2013 when he scored his first goal for Tranmere Rovers, in a 2–1 loss against Fleetwood Town in the first round of the League Cup.Since making his debut for the club, he started in every matches until he suffered a groin injury in late–September.