James Harrison has hit back at criticism from his former Pittsburgh Steelers team-mates following his controversial move to the New Year England Patriots.

The veteran linebacker signed on with the Patriots just three days after an acrimonious exit from the Steelers.

Center Maurkice Pouncey said Harrison "erased his own legacy here," while adding "He wanted to go. ... He needs to come out and admit that."

Bud Dupree added it felt like Harrison "went to the Patriots just to spit in Coach [Michael] Tomlin and Mr [Art] Rooney's face." 

However, Harrison has responded with a lengthy post on Instagram, defending himself by posting a series of pictures with a typed out message on his Instagram account.

"This will be my only comment," Harrison captioned the series of photos.

"If anybody thought I signed a two year deal with a team in the NFL at age 39 to sit on the bench and collect a check and a participation trophy, they're mistaken. 

"I didn't sign up to sit on the bench and be a cheerleader. I was clear about that when I signed and I was told I would be on the field when I signed. 

"When I was asking for reps in camp, I got none. I got lip service though: We know what you can do - you don't need the reps. But I know what my body needs in order to be in shape to compete, and I said so, but still zero reps. 

"At the beginning of the season when it was clear I didn't have a role anymore, I asked to be released. Throughout the season, I was told week in and out that I'd be used. I wasn't. 

"I started getting frustrated about the whole thing. I asked to not be dressed or take unnecessary practice reps if I wasn't going to play. 

"That happened for a couple of weeks, then we had a game week that I got solid reps in practice and everyone assumed I would play. I got to the stadium four hours early as usual, and my locker was empty. Nobody said anything to me about being inactive, just an empty locker. I asked to be released again. I was told no. 

"A couple weeks later, they dress me for the game so I assume I'm going to play, and I get zero reps. Stood on the sideline the whole game. I asked to be released again. I was told no. 

"Then a few days later, they released me. I was never told I would be brought back, it was: If I bring u back, be in shape. I cleared waivers, and they didn't call. New England called.

"Maybe I didn't handle my frustration the best that I could've. If you haven't learned anything about me over the last 16 years, I'm a competitor to my core. I live and breathe competition. I do what it takes to keep my body and my mind ready to be on that field. I do it for me, I do it for my family, I do it for my team, and I do it for the fans. Nothing else to it. At the end of the day, they made a business decision, and so did I."

Harrison, 39, was cut by Pittsburgh on Saturday to make room for tackle Marcus Gilbert's return but signed with New England on Tuesday following a visit to Gillette Stadum.