Paul Daley is known by MMA fans for two things: sucker-punching Josh Koscheck after their UFC 113 bout and continuously missing weight.
Marquardt is being brought into Strikeforce despite being cut by the UFC a year earlier due to failed medical tests.
When the news first broke that Marquardt failed his "medical requirements," Dana White was livid. He said at the time that Marquardt would not longer be with the UFC.
Less than a year later, and with some further understanding regarding Marquardt's situation, White has signed him with Strikeforce. What does that say about how little interest White has in bringing Daley back?
It appears recently that although White has let time heal some of the wounds Daley left by punching Kos after the final horn, he is also less than impressed with what he has done since. Missing weight and beating lesser talent by decision is not the fast track back into the UFC.
When Dana cut Paul Daley following the 2010 fight/incident, he was disgusted (as most fans were) with Daley's actions. There are too many variables to really gauge if Daley will ever be back in the UFC, but having a spot taken in Strikeforce by Nate Marquardt may leave Daley on the outside looking in.