The Scotland international, who joined from Norwich City in June, dislocated his kneecap away at QPR on August 16 and has undergone an operation.
The 26-year-old faces six months out but his boss expects that, with time allowed for rehabilitation, a return to action before pre-season is unlikely.
"It looks as though he will be out for six months but, in my experience, that practically rules you out for the season," Bruce told reporters. "It's six months, then probably two months of rehab.
"If I'm being honest, I doubt we'll see him until next pre-season."
The setback is a major blow in Snodgrass's career, although Bruce knows that it could have been even worse for the Scotland international.
The Hull boss added: "Robert dislocated his kneecap and subsequently damaged the ligaments that hold the kneecap in place. Thankfully he hasn't damaged the cruciate as we first thought but the state of the injury isn't good.
"It's devastating for him and for us. A lot was invested in him to give us something a little bit different from midfield. It's tough luck but that's football."
Bruce also has to deal with concerns over goalkeeper Allan McGregor's fitness ahead of Sunday's meeting with Stoke City, the No.1 having picked up a shoulder injury.
"McGregor is a bit of a worry as he has hurt his shoulder," the former Sunderland manager added, "but everybody else is okay.
"We made nine changes the other night [when Hull lost 1-0 to Lokeren] so hopefully we'll be fresh enough. To win a game in the Premier League, your performance has to reach a certain intensity so we have to be fresh enough to reach that.
"To get back-to-back wins in the Premier League would be great. I don't think we've done that for about a year so it shows how hard it is."