In filing #2012 Samsung says this:

  3. In response to Samsung’s motion detailing Velvin Hogan’s failure
 to reveal his litigation with Seagate during voir dire and its impact on the
 integrity of the trial and the verdict, Apple demanded that Samsung
 disclose the timing of its knowledge regarding those facts. A true and
 correct copy of Apple’s email, along with further correspondence
 between counsel for the parties that resulted in Apple’s agreement that any
 such disclosures would not constitute a waiver of any privilege, is
 attached hereto as Exhibit A. By way of separate declaration,
 Samsung is confirming to Apple that it did not know of Mr. Hogan’s undisclosed
 litigation against Seagate until after the verdict. To date, Apple has not
 revealed whether it was aware of Mr. Hogan’s litigation against Seagate
 prior to the verdict or prior to Samsung’s Motion.

According to Groklaw, Apple asked via email and Samsung has denied this in a filing.

"By way of separate declaration, Samsung is confirming to Apple that it did not know of Mr. Hogan’s undisclosed litigation against Seagate until after the verdict." --Samsung, #2012

http://www.groklaw.net/article.php?story=20121002201632770

I believe that is entirely possible, legal, and wise.

It might be legal, but if found out it would almost certainly get their motion denied, which is why Apple aggressively pursued a statement from Samsung about whether or not they knew. As a result, Samsung has made a declaration they did not know, and so at this point if it later turns out they did now, they're in trouble.

More wise would have been just to remove him from the jury during jury selection. Overturning a jury's decision is pretty rare.