Fredii, he was approached for the first and second one but turned em down
First time was due to him not liking the Director due to lawsuit they had against each other years ago.
The second time was due to Van Damme being in it. According to IGN, years ago Stallone had a party at his house full of Hollywood actors etc. Seagal was there boasting about how he was the best etc, then Van Damme walked over to him and challenged him to a fight outside, Seagal then went all quiet, refused and left the party.
Van Damme then followed him to a club and challenged him again, to which he again refused haha