Arizona Cardinals' J.J. Watt tweets he's set to play days after having heart procedure 12:37 PM ET Josh WeinfussESPN Staff Writer Close Covered the Cardinals since 2012 Graduate of Indiana University Member of Pro Football Writers of America CHARLOTTE, N.C. -- Arizona Cardinals defensive lineman J.J. Watt tweeted Sunday, hours before he was set to play against the Carolina Panthers , that he went into atrial fibrillation on Wednesday and had to have his heart shocked back into rhythm on Thursday. He sent the tweet at 12:14 p.m. ET. The Cardinals were set to kickoff at 4:05 p.m. ET. Watt, who's in his second season with the Cardinals, said he will play against Carolina. The reason Watt said he tweeted the information because the news of his heart condition and the procedure was leaked. Watt missed practice on Wednesday and Thursday for what the Cardinals listed as "calf/illness" on their injury report. According to the Cleveland Clinic, atrial fibrillation is "an irregular heart rhythm that begins in your heart's upper chambers."