Rams Star Chris Long -- I'M PROUD OF MICHAEL SAM ... 'Excited to Play with Him'

Michael Sam is impressing his St. Louis Rams teammates -- on and off the field -- so says superstar Chris Long who tells TMZ Sports he's proud of the guy and can't wait to play with him.

After Sam was honored with the Arthur Ashe Award for Courage at the ESPYs last night, Long says he was getting a lot of positive text messages from other players on the Rams.

"I've been hearing a lot of really great feedback," Long says ... "To be able to go up there, when he was nervous I'm sure, and speak about such an emotional topic is impressive."

During the speech, Sam thanked the Rams for supporting him as he tries to become the first openly gay football player to take the field in an NFL game. Long says he's heading in the right direction.

Long also says Sam has done a great job managing the media circus that's been surrounding him ever since he went public with his sexuality.

"When he's been on the football field, it's been all business ... and the team supports him."

Long adds, "He's a great kid."