Luck missed last week's game against the Jaguars (the first game he's missed in his NFL career) due to an injured throwing shoulder, and that has left his status in question for tonight's game as well. He is officially listed as questionable on the injury report after being limited in practice this week, and though he's getting closer to being ready, there are still questions about whether that return will be tonight. The hope is certainly that he will be ready, but a lot of it depends on how his shoulder reacts and how he is feeling. Last week, the Colts realized that he just didn't have the arm strength to go out there with a painful injury - will they think he's ready enough this week?
According to ESPN's Adam Schefter, that's still very much up in the air, as he reported that the Colts are still uncertain whether Luck will play. Schefter said that Luck will test his shoulder sometime today so that they can get a better idea, but that "the Colts are prepared to start [Matt] Hasselbeck if need be." In fact, team and league sources told Schefter that "it would not be a surprise if it were Matt Hasselbeck" starting tonight against the Texans instead of Andrew Luck.
Matt Hasselbeck played well enough last week, completing 30 of 47 passes (63.8%) for 282 yards and a touchdown without turning the football over, helping the Colts to a 16-13 overtime victory. He wasn't great, but he was absolutely good enough as a backup stepping in for Luck. He might have to do it again tonight, but it will be even tougher for him this time if that were the case, as he has been dealing with an illness that kept him out of practice on Tuesday. He was a full participant on Wednesday, however.
After tonight's game the Colts will have a ten-day gap until their next game (when they host the New England Patriots on Sunday Night Football), so Luck could have more time to rest. The Colts want their franchise quarterback out there, but they also realize that they need to do what is best for Luck and for the team, and if there's a chance of Luck doing more damage by playing or if Luck just doesn't have the arm strength needed to make some of the throws, the Colts know they have Hasselbeck ready if need be. As of right now, however, it sounds like not even the Colts know yet who it's going to be taking the field for them at quarterback tonight.
UPDATE: According to multiple reports, Matt Hasselbeck - who was in the hospital earlier this week with an illness - will start at quarterback for the Colts instead of Andrew Luck.