Injuries and other roster issues are among the things the committee considers when they meet to select and seed the field. A key factor in how they are considered is whether or not a player will be available for the tournament.
If a player missed some games but will be available, the committee may give some consideration with regard to seeding, putting more weight on a team's performance with that player than without him. However, the committee will not go so far as to ignore losses that occurred without the player or assume the team would have won a game had they been at full strength. Missouri, which didn't have star Laurence Bowers for a handful of games, may benefit from this.
Injuries appear to have no bearing on selection, though. A team has to earn its way in on its own merits.
If a player is not going to be available for the tournament, the committee will generally put more weight on how the team played without that player. How much information the committee has in that regard depends on when the player in question got hurt.
The most recent high-profile case of this was in 2010, when Purdue's Robbie Hummel went down late in the season. The Boilers were well on their way to a No. 1 seed when Hummel tore his ACL at Minnesota with just three games to play in the regular season. Even though Purdue did go on and capture a share of the Big Ten title, it was clear the Boilermakers were not the same team without Hummel. The Boilers' profile at the end of the year would have merited a two-seed, but the committee made them a four.
The most famous case of something like this was in 2000. Cincinnati was about to be named the overall No. 1 seed of the tournament, but national player of the year Kenyon Martin suffered a season-ending injury in the first game of the Conference USA tournament, which the Bearcats went on to lose. The committee had almost no information to go on regarding how Cincinnati would play without Martin, but instead of making them a top seed, they dropped the Bearcats to a two.
Kentucky is not nearly so high to begin with. They need to prove themselves again to the committee (if they even had in the first place). The Wildcats will have to show they can play tournament-quality basketball without Noel. If they can't, they won't get selected. It's that simple. They have seven regular-season games left, including two at home with the SEC's top two teams, so there are opportunities to prove themselves. We'll just have to wait and see if they can.