Terrible news from MMAMania...Frank Mir has sustained a knee injury and will not be able to fight Brock Lesnar at UFC 98. Apparently it required "minor" knee surgery. When I wrote about how UFC 98 might cause chaos, I was certainly not thinking it would be this bad. Mir's injury derails the hopes of a unified UFC Heavyweight Title and probably puts Lesnar on the sidelines. The only other possibility would be to book the winner of Gonzaga/Carwin into the UFC 98 main event against Lesnar. The turnaround time is a little tight, though. You would need the winner to emerge without any injuries and even then it's tough.
More likely we will see the Lesnar/Mir bout rescheduled for later this summer and they'll move Evans vs Machida/Jackson to UFC 98. That's my best guess, at least.
UPDATE: MMAWeekly claims the recover time from the surgery will be 4-6 weeks.