Luke Rockhold’s first middleweight title defense will be a rematch, but not the one he expected a month ago.

Rockhold was scheduled to defend his crown against former champ Chris Weidman in the UFC 199 headliner Saturday in Inglewood, California, six months after Rockhold TKO’d the Long Island native. An injury to Weidman opened the door for veteran Michael Bisping, who lost by submission to Rockhold in November 2014, to earn his long-coveted title shot.

Ahead of their pay-per-view main event, here’s a guide to MMA’s 185-pound division with UFC fighters separated into tiers plus some of the top non-UFC talent in the sport.

Champion

Luke Rockhold (15-2, 5-1 UFC)

Rockhold tapped out Bisping and former light heavyweight champion Lyoto Machida in the lead-up to his championship victory. The well-rounded, 31-year-old former Strikeforce champion also holds key wins over Ronaldo “Jacare” Souza and Tim Kennedy.

True contenders

Yoel Romero (11-1, 7-0), Ronaldo Souza (23-4, 6-1), Chris Weidman (13-1, 9-1)

Weidman had reigned as champion since stunning longtime kingpin Anderson Silva in 2013 and winning a rematch before his first professional defeat in December.

Romero won a hotly-debated decision over Jacare in December, but a failed drug test due to a tainted supplement led to a suspension. Souza, for his part, has won nine of his last 10.

Upper echelon

Vitor Belfort (25-12, 14-8), Michael Bisping (28-7, 18-7), Tim Kennedy (18-5, 3-1), Lyoto Machida (22-7, 14-7), Anderson Silva (33-7, 16-3)

The bulk of his group is poised for a sharp decline in the near future as some of the division’s up-and-comers mature.

Bisping, the late replacement for UFC 199’s main event, is coming off a narrow victory over Silva.

Belfort and Machida are coming off disappointing losses within the past 12 months, while Kennedy hasn’t competed since a September 2014 loss to Romero.

Muddled middle

Derek Brunson (15-3, 6-1), Uriah Hall (12-6, 5-4), Gegard Mousasi (38-6-2, 5-3), Rafael Natal (21-7-1, 9-5-1), Robert Whittaker (16-4, 7-2)

Whittaker and Brunson have been on a roll of late and could find themselves in the title picture next year.

Mousasi and Hall, both talented strikers, can’t seem to put together long enough win streaks to break through in the crowded 185-pound division.

Natal, a Brazilian who trains in Manhattan, saw his four-fight win streak snapped by Whittaker in April.

Best of the rest

Dan Henderson (31-14, 8-8), Thales Leites (25-6, 10-5), Hector Lombard (34-5-1, 3-3), Thiago Santos (13-3, 5-2), Brad Tavares (13-4, 8-4)

Santos has some upside, and it’s possible Tavares still does as well. But Henderson will be 46 in August and any fight could be his last at this point.

Leites could ascend a tier with a big win, but he’s unlikely to ever receive a second title shot.

Lombard, returning after a four-fight stint at 170 pounds, can knock out anyone but cardio issues limit his ceiling.

Outside the octagon

David Branch (18-3, 2-2), Mamed Khalidov (32-4-2, 0-0), Yushin Okami (31-10, 13-5)