PASADENA — It wasn't long ago that the Rio Hondo League was known for its parity.
League champions changed yearly and every team didn't go more than a few seasons without reaching the playoffs.
Over the last few years, however, those trends changed, starting at the top.
The Monrovia High football program has captured four straight league crowns and is in the midst of a 17-game league winning streak as league play begins Thursday.
The Wildcats' physically-tough nature and talented playmaking capabilities are embodied by their blue chip defensive end Ellis McCarthy, a 6-foot-4, 310-pound specimen who has offers from virtually every PAC-12 school.
However, while the Wildcats seem like an overwhelming favorite, there are vulnerabilities.
For starters, McCarthy's play has been limited, as he injured his knee in the second game this season.
Also, Monrovia's brutal schedule has them 1-4 heading into Thursday's league opener at La Cañada, which is also 1-4.
"The thing about the Spartans is they're always able to get up for Monrovia," La Cañada Coach Dan Yoder said. "We have to look at them just as any other team. If we can execute, we can make things happen. We just have to keep it going for 48 minutes."
League opponents may actually serve as relief for La Cañada, as four of the Spartans' five nonleague foes — Maranatha, Arroyo, Crescenta Valley and Alhambra — are ranked in the CIF Southern Section Division polls.
The Spartans have been without starting quarterback Matt Jones, who suffered an injury against Crescenta Valley on Sept. 23 and has sat since.
Jones' replacement, Grant Owen, has completed eight of 27 passes for 51 yards while running for 181 yards and two touchdowns on 28 carries.
Fullback Kyle Herron and tailback Andy Paynter have led La Cañada's ground game.
Herron has run for a team-best 193 yards and two touchdowns on 33 carries while Paynter has rushed for 141 yards and two scores on 20 carries.
There's a high level of excitement at South Pasadena, purposefully cultivated by first-year head Coach Marty Konrad.
"We had a good [nonleague] schedule and some competitive games," Konrad said. "Now all that matters is league and we have a big opener at Temple City."
Konrad's gamble to start sophomore quarterback Joey Harmon has paid dividends, as the youngster has limited mistakes and found a reliable target in senior tight end Justin Cornford, who hauled in seven receptions for 112 yards against Maranatha on Friday.
Defensively, the Tigers have been up and down, allowing 11 points per game in three wins but surrendering 31 points per contest in two defeats.
South Pasadena (3-2) is hoping to end the league's longest playoff drought by reaching the postseason for the first time since 2003.
As for San Marino (3-2), first-year Coach Mike Hobbie believes his Titans can advance to the postseason after missing out last year.
"To be honest, I don't know much about the other teams in league," Hobbie said. "Call me old-fashioned, but I focus my energies on my team. If we execute and do what we're supposed to, we'll be fine."
The Titans upset Golden Valley, 38-20, on Thursday behind an opportunistic defense that forced seven turnovers in that game and 12 during the preseason.
Ideally, the run-heavy Titans prefer to pound the ball behind running back Kwame Do, who is averaging 127 yards per game.
Of course, San Marino's success hinges greatly on do-everything junior Matt Wofford, the team's quarterback, kicker, punter, kick returner and defensive back.
San Marino travels to Muir to open league versus Blair on Friday.
Despite a 1-4 record, Blair can't be overlooked.
The Vikings commenced the season with a 25-14 win over Fulton and have been competitive in their last two nonleague losses.
"We're doing our best to field a team and teach these young men about football and life," Blair Coach Gary Parks said.
While most Rio Hondo League teams number in the 40's or 50's, the Vikings' opening-day roster included 17 players.
Blair's Antavion Allen is a potential game-breaker at running back and defensive back.
Blair is hoping to win its first league game since 2007.
In that season, the Vikings finished 4-1 in league, split the league championship with Monrovia and were the last team to defeat the Wildcats, 38-26, on Oct. 26.