There are times when a UFC fight gets a whole lot more interesting due to a late change of opponents. Over the course of the past three days, that has happened twice.

In the most time-sensitive switch, Chris Wilson was scratched from Saturday's UFC 98 card with barely two days' notice, after the Nevada State Athletic Commission could not get Wilson's doctor on the phone to provide necessary medical information. The NSAC reportedly left numerous messages for the doctor and simply never got a call back. As a result, the commission was left with no choice but to pull Wilson from the show.

Wilson's replacement against Brock Larson will be Mike "Quicksand" Pyle (17-5-1), an Xtreme Couture fighter making his UFC debut after lots of experience elsewhere, including EliteXC, Affliction, Strikeforce, WEC and the IFL. Pyle has won his last four fights (all via submission), and six of his past seven bouts. Pyle's only loss during that stretch was to Jake Shields in Nov. 2007.

Earlier this week, another late switch resulted in an intriguing heavyweight battle that just might put the winner on the radar for a possible title shot vs. Brock Lesnar (or Frank Mir , pending the outcome of that title fight at July's UFC 100).

"The Texas Crazy Horse" Heath Herring pulled out of his UFC 99 bout vs. up-and-comer Cain Velasquez on June 13 in Germany, citing either illness (as reported by MMA FanHouse) or injury (as reported by the UFC) as the cause. Either way, his replacement is a solid test for the former collegiate wrestling standout, as Velasquez will now battle Cheick Kongo .

Kongo (14-4-1, 7-2-0 UFC) has won five of his last six fights, with the only loss in that time frame coming at the hands of Herring in March of 2008. Since then, Kongo has made quick work of Dan Evensen , Mustapha Al-Turk and Antoni Hardonk .

Velasquez (5-0-0, 3-0-0 UFC) won his first four fights via knockout in the first round, and his most recent bout -- vs. Denis Stojnic at February's UFC Fight Night 17 -- via TKO at 2:34 of Round 2.

A standout wrestler at Arizona State, Velsaquez has the athleticism, punching power and solid wrestling base that has many observers calling him the future of the UFC heavyweight division, and a potential rival to Lesnar in years to come.

Here we go with the big boys: Brock Lesnar vs. Heath Herring is next.

Round 1: Lesnar runs out with a flying knee that misses. He circles a bit before dropping Herring with a right hand and rushing in for a guillotine, which isn't sunk in well. Herring has Lesnar against the fence. Lesnar shoots and gets an easy takedown with Herring back against the cage. Lesnar stands over Herring and tosses his legs aside. Herring to his hands and knees with Lesnar on his side. Herring turtles up. Lesnar throwing punches to the sides of Herring's head. Herring is bloodied. Herring rolls over briefly trying to take guard but Lesnar keeps that from happening. Lesnar still busy with punches and elbows to the head. Knee to the body by Lesnar. Lesnar is controlling Herring with an ankle pick and a wrist, textbook amateur wrestling style. Herring can't get off his knees. His left eye looks like it's swelling. Lesnar just holding Herring in place and striking at will as the round ends. Lesnar 10-9, easily.

Round 2: Lesnar charges forward for a takedown and Herring avoids it. Herring throws a fist and Lesnar ducks under for a body lock takedown. Lesnar gets Herring right back to his knees. Herring rolls over and Lesnar takes side control. Herring turns to his knees again. Lesnar gets full mount but Herring rolls back to his knees. Lesnar hammer-fists Herring in the face. Lesnar with knees to the body. Herring rolls to his back again. Herring tries to take half guard but Lesnar maintains side control. Herring fights to his feet. Lesnar with another guillotine with his back to the fence. Lesnar knees Herring in the body. Herring with a couple of knee strikes and throws a combo of fists that miss the mark as the round ends. 20-18 Lesnar.

Round 3: Both of Herring's eyes are swelling and he looks in rough shape. Lesnar throws a kick to the head. Herring throws fists and forces Lesnar against the fence. Lesnar reverses it and throws more knees to the ribs. Lesnar takes Herring to the mat again and resumes punching Herring in the face from the side. Lesnar with big knees to Herring's ribs and shoulder. For those wondering about Lesnar's stamina in a long fight, he looks completely fine at this point. Herring rolls to his back and Lesnar takes full mount again. Herring rolls back to his knees. Lesnar is manhandling Herring on the canvas. Herring sits on his backside and Lesnar tries a to force a rear naked choke, but Herring slips out and gets back to his feet. Herring throws a couple of strikes that miss and Lesnar takes him down again. More fists to the face by Lesnar. Herring rolling back and forth but he just can't escape. Lesnar with full mount again. Lesnar hears the ten second warning and starts celebrating early, letting Herring back up as the buzzer sounds. 30-27 for Lesnar, by my estimation. Lesnar has clearly improved since the Mir fight.

Winner: Brock Lesnar defeats Heath Herring via unanimous decision (30-26, 30-26, 30-26) after three rounds.

"I fell off the horse against Frank Mir, and tonight I got on that horse and rode it out of town, baby!" a jubilant Lesnar says after the win.

The UFC has got to be happy with that performance, and while Lesnar still shows the need for improvement in certain areas (he had full mount numerous times and couldn't do anything with it except control position), he's coming along just fine for a rookie.

I'll have a live blog of UFC 87 starting later tonight, at roughly 9:45 p.m. ET. Be sure to check back for round-by-round coverage of the fights.

Everybody made weight on Friday, with Brock Lesnar once again getting a hero's welcome:

PPV fights:

• Jon Fitch (170) vs. Georges St. Pierre (170)
• Heath Herring (250) vs. Brock Lesnar (265)
• Roger Huerta (155) vs. Kenny Florian (155)
• Demian Maia (185) vs. Jason MacDonald (185)
• Robert Emerson (155) vs. Manny Gamburyan (155)

Undercard fights:

• Tamdan McCrory (170) vs. Luke Cummo (167)
• Dan Evensen (244) vs. Cheick Kongo (235)
• Andre Gusmao (205) vs. Jon Jones (205)
• Steve Bruno (170) vs. Chris Wilson (170)
• Ryan Thomas (170) vs. Ben Saunders (170)

Random thought: If Brock Lesnar loses to Heath Herring, will fans allow him to work his way up from the bottom of the roster like any other rookie would, or will he be crucified for not becoming an elite-level fighter within his first three fights?

My guess is there will be a loud contingent of fans saying that Brock sucks and writing him off for good, just because he couldn't waltz into the top promotion in the sport with a 1-0 record and immediately dominate guys like Mir and Herring. People forget that Brock never really got the chance to work his way up the ladder. The guy has two professional fights on his record as we speak, but he's being talked about as a total bust if he can't beat guys with years of experience.

Brock could smash Herring and all of this would become irrelevant. But if he loses, will UFC fans allow him to start fighting guys with similar experience without crying that he's being "protected"? Something tells me there will be some serious ignorance flying around the internet if and when Brock goes 0-2 in the UFC. Give the guy a chance to learn.

They're getting ready for Heath Herring vs. Cheick Kongo. From the prefight interviews:

Herring: "I feel pretty confident for this fight."
Kongo: "I don't care."

Round 1: Herring puts Kongo down with a punch within the first 10 seconds but Kongo is back to his feet so fast it might have been more of a slip than anything. Kongo with a takedown. Herring rolls through to take top control. Herring has Kongo against the cage on the ground. Kongo fights back to his feet and has Herring back against the cage, with Herring holding him in a front facelock. Kongo is doing his famous knees to the inner thigh that missed their target in the Cro Cop fight. They are grappling for position with Kongo reversing and briefly getting back control on the mat, but he stepped away from it. The crowd is booing with 20 seconds left in the round, but honestly, it's been a very good and active fight so far, especially for a heavyweight bout. Very hard round to call, but I'll give it to Herring 10-9.

Round 2: Kongo controls Herring again on the ground and then decides to let Herring up... kind of. He wants Herring to stand, but he won't back off enough to allow it. The ref finally stands them (Herring) up. Herring rushes in with strikes and quickly winds up grappling on the cage again. It goes back to the ground with Kongo controlling first, then Herring reversing for side control. Herring with a series of big knees to the side. Kongo is looking at the clock and taking knee after knee without trying to improve position. The round ends, and that one is Herring 10-9.

Round 3: Both guys land big shots to start and Herring applies a guillotine. Kongo slips out. Kongo gets Herrings back but Herring escapes and shoves him off. They wind up against the cage again and Herring gets side control. Herring starts punishing with knees to the ribs again and twice rears back with the knee closest to Kongo's head, and thinks better of it and stops himself. Kongo gets in this position and just holds on and takes every shot. Full mount for Herring and he hammers away at Kongo's head as the round ends. Herring 10-9. Even though I've given all three rounds to Herring, I could see either of the first two rounds being scored for Kongo, so it's not like Herring ran away with it or anything, but I do think he deserves the decision. We'll see.

Winner: Heath Herring defeated Cheick Kongo via split decision (29-28, 28-29, 29-28) after three rounds.

This is a huge win for Herring. He looked a lot better than in recent fights, going the distance without gassing and seemingly much more motivated. Herring mentioned after the fight how unexpected it was that Kongo didn't opt to strike more.