What do I mean? Well look at their careers, they both have a history of great regular season success. They also both have a career of post season failure. So sure, there are some similarities, but how comparable are they?
Ok, lets start by looking at Regular Season success.
Since Joe Thornton came into the league he has averaged just over a point per game for his entire career. On top of that his points per game averages are skewed down quite a bit by his rookie year. That year he played in 55 games and only scored 7 points. Not what one would expect from a #1 overall pick, especially if you see the impressive numbers for the rest of his career. However he didn't get much ice time. Coach Pat Burns believed in bringing him along slowly, which has apparently worked out pretty well for Thornton.
Since coming into the league Thornton has won the regular season MVP trophy (the Hart), and the regular season scoring trophy (the Art Ross trophy). So he has proven himself offensively. On top of that he has been an All Star 7 times (the last time in 2009 he was the team captain).
He is perenially one of the, if not the, team leader in points on his team. And his teams always do great with him in the regular season. His teams are routinely in the playoffs (9 out of 12 seasons that he's played), and he has been on a team that has won the President Trophy (with San Jose in 09) and on the best team in his conference twice (once in 09 with the Sharks, and another time with the Bruins)
Now for A Rod
His regular season stats are pretty well known, and even more impressive than Thornton's are. He has hit over 50 home runs three different times. Hell he has only had three seasons with less than 30 home runs. On top of that he has only had three seasons where he didn't have at least 100 RBIs. Oddly enough the same three years that he didn't get at least 30 home runs. So his starts are right up there. Just like Thornton he is usually among the stats leaders, if not the stat leader, on his team.
He has also won his share of regular season accolades. He has been a 12 time all star, he has been the MVP of the league 3 times, the Sporting News Player of the year. The list goes on and on. Its an incredibly impressive list.
One difference is that A Rod's teams are not always among the best teams in the league. Actually a lot of people argue that the teams are worse after he arrives. I honestly don't quite believe that. His teams are not always among the best teams in the league year over year, but they are generally competitive enough that you could argue he doesn't make them worse.
Post Season
Now Joe Thornton in the post season, stats wise, hasn't been horrible, but his teams aren't exactly setting the world on fire. Someone has even named a an award for bad playoff performances after him. His points per game average is way off of his regular season stats. With only 53 points in 76 games his points per game is only .69. So he doesn't have as much success in the playoffs, but do his teams win? Well he has played in the playoffs in nine different seasons but only made it to the second round of the playoffs four times. (once with the Bruins in 98-99, and three times with the Sharks). Twice he has been on a team that was the #1 seed in the conference and both times they lost to the #8 seed. So in the playoffs, its just not pretty, his teams just don't win.
For A Rod the numbers aren't quite so clear. Its a lot harder to make it into the playoffs in Baseball so its not as if he has had as many opportunities to be in the playoffs. That being said his numbers are obviously way down in the playoffs. He's played 39 post season games and only has 7 hr, and 17 RBIs. So during the regular season he hits a home run in roughly 25% percent of his games, but in the playoffs he's down to only 17% (I know HR per AB is a better way to compare this, but I didn't have those numbers on hand sorry). On top of that his RBIs per AB goes down tremendously, and his batting average goes down from .306 to .279 so all in all his stats are noticeably down.
The last thing I want to consider his how clutch they are.
Honestly they both have a bad habit of coming up huge in non clutch situations, and not coming through when its neccessary. A Rod has been known to get a grand slams when his team is already up by a large lead, and striking out when they need him to hit.
Thornton has the same problem A lot of his points seem to come in garbage time. The only time that I can say I that this didn't happen was game 5 of the 2009 playoffs. His team had to win, and they did 3 - 2, with Thornton getting a goal and two assists. If he did that more often I wouldn't be writing this, but instead, in the games before and after that he got absolutely no points. A player of his caliber can't do that if he wants to get far in the playoffs.
So is Thornton the A Rod of hockey? Honestly I'd say yes. If you look at the types of careers they both have great regular season success, and a lot of post season failures.
Its a shame. I was a Thornton fan from the get go in Boston, and I love watching him play. I still think he is one of the best players along the boards in the NHL. He is so strong on the puck and is great at digging it out to his teammates. He has a great shot, but he needs to use it more. And his ice vision is awesome, but I'm really glad that Boston got rid of him. The team would never have gotten a chance at the cup with him here, then again, we haven't won a cup since he left.