Four Democrats and a single Republican are on the ballot Tuesday in a special election for the seat formerly held by state Rep. Justin Rodriguez, D-San Antonio.

Rodriguez was appointed a Bexar County commissioner last month. His departure from the Texas Legislature triggers the fourth Capitol special election since the November midterms.

None of those special elections has flipped party control of a seat, and the one in Rodriguez's House District 125 isn't expected to either. But there's a bit more intrigue in the race for his seat because it's likely to go to a runoff and because it features a GOP candidate, Fred Rangel, who has won the support of some of the state's top Republicans.

Among the Democrats, Ray Lopez is seen as a top contender. He represented the area on the San Antonio City Council from 2009-17, he has easily led in fundraising and he has been endorsed by three San Antonio state representatives.

The other Democratic candidates offer compelling cases, too. Education policy advocate Coda Rayo-Garza is the fresh face in the race — and the only woman — with endorsements from Annie's List and prominent female Democrats such as 2014 Democratic gubernatorial nominee Wendy Davis. Rayo-Garza also has the backing of the San Antonio Express-News editorial board.

Like Lopez, another Democratic candidate, Art Reyna, has elected experience in the area — he held the HD-125 seat from 1997 to 2003. He has since served on the City Council in Leon Valley, an enclave on San Antonio's Northwest Side.

Rounding out the Democratic lineup is Steve Huerta, an activist whose campaign has run into a few problems. The Express-News reported last month that he is running afoul of eligibility requirements by having been convicted of a felony — stemming from a 1999 drug-possession charge — and not living in the district for at least a year before filing.

The fractured Democratic field could provide an opening for Rangel, a businessman and activist, to make a runoff in the solidly blue district and hope for the best in a low-turnout environment. The scenario could echo that of Pete Flores, the Pleasanton Republican who pulled off an upset last year in the special election runoff for Senate District 19, also in Bexar County.

Gov. Greg Abbott endorsed Rangel last week, and U.S. Sen. John Cornyn backed Rangel on Monday, saying, "San Antonio Republicans have a tremendous opportunity to win back a valuable Texas House seat." Rangel's high-profile endorsements are touted in a radio ad that he has run in the final days of the race, which has also seen a Democratic political action committee launch a late offensive against him scrutinizing his business record.

Early voting ended Friday, and turnout was expectedly dismal. According to the Bexar County Elections Department, 3,354 people voted early in person.

Even if the HD-125 race is settled Tuesday night, there remains one last vacancy in the Legislature: the seat formerly held by state Rep. Carol Alvarado, D-Houston, now a state senator. Late last month, Democrats Christina Morales and Melissa Noriega advanced to a yet-to-be-scheduled runoff for the seat.

Polls are open from 7 a.m. to 7 p.m. Tuesday in HD-125.

Disclosure: Annie's List has been a financial supporter of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune's journalism. Find a complete list of them here.