There was some optimism when NFL and NFLPA officials met for two hours in Dallas this past Saturday as they work to resolve their differences and create a new collective bargaining agreement.

The two sides met again Wednesday to try and hammer out a new deal before the March 4 deadline and avoid a potential lockout. New developments Thursday tempered that optimism however.

NFL.com reported that Thursday's five-hour meeting was canceled, according to sources. No reason was given for the cancellation.

Then, ProFootballTalk reported that an owners meeting scheduled for next week in Philadelphia also was canceled.

The key issues in negotiations continue to be how to split up around $9 billion in annual revenues, an 18-game season and rookie wage scale.

In case you missed it several weeks ago, I thought Mike Florio did an excellent job with this piece explaining some of the key questions and issues in this labor situation. It's definitely worth a read.

Meanwhile, NFL teams can begin placing franchise and transition tags on their free agents today. It's unclear whether the Vikings will use either tag. Linebacker Chad Greenway and wide receiver Sidney Rice are the two most likely candidates if the team decides to use either tag.

Judd looked at whether the Vikings could or should use the tags in a previous blog.