Jorge Posada is an interesting case. It is his first time on the ballot.
He had a 17 year career, all with the Yankees. He hit .273/.374/.474 with 275 home runs in 1829 games (1574 as a catcher). He had a 42.7 bWAR. He made 5 All-Star teams, and had 5 Silver Slugger awards. He received MVP votes twice, finishing 3rd (2003) and 6th (2007).
He played in the playoffs 15 times and has 4 World Series rings.
There are only 15 catchers currently in the Hall of Fame. Catchers kind of deserve a different scale than other positions. Comparing Jorge to them, 5 hit more home runs, 10 had a better batting average, 5 had a better OBP, 7 had a better slugging average and 7 had more RBI.
If we talk defense, it is hard to figure how Posada would fit. He never won a Gold Glove. He wasn't thought of as a great defensive catcher, but was considered a good handler of pitchers. And he was thought of as a leader on a team that made the playoffs almost every year.
I'm likely the wrong person to ask, I have a personal dislike for the Yankees. I see Posada as close to the Hall, but likely not quite there. Most of the 'modern day' catchers in the Hall played more games at the position.
A lot of the question about putting him in the Hall revolves around how much credit you give him for the Yankees being in the playoffs so many times in his career. He was an important part of the team, but was the rest of the team good enough to win with an average catcher?
You can look at Jorge's stats here.
A lot of debate about the Hall of Fame relates to comparing a candidate against others elected and excluded. The chart below shows all players who played the majority of their career after 1945 (excluding active players, and those on the ballot or yet to hit the ballot) according to how long they played and how productive they were. TRC+ is wRC+, just for all runs rather than just batting runs. This is not meant to be definitive, but a high level starting point showing how players with similarly productive and lasting careers have fared.
Similar Players: Catchers don't fit well into this framework since they start fewer games and not all aspects of catching are currently reflected in most public value systems. Among catchers, Posada is most similar to Bill Freehan, Lance Parrish and Thurmon Munson.