He was named the Player of the Year last season and was the subject of a failed £2 million bid from Newcastle United boss Alan Pardew in January.
"When clubs put bids in for you it is always very flattering," Mariappa told the Reading Chronicle. "It shows I must have been doing something right.
"But I continued to keep my head down and focus on my football. Thankfully, that has taken me to where I am today."