The NFL free agency negotiating period begins Monday, and the market will open at 4 p.m. Wednesday. The Lions have been active in free agency under Bob Quinn, too, handing big contracts to players like receiver Marvin Jones in 2016 and offensive linemen T.J. Lang and Rick Wagner in 2017. MLive will mull possible fits for 2018 in the coming days. Today: running backs.

Under contract for 2018: Theo Riddick ($4.1 million cap hit), Ameer Abdullah ($1.3 million), Dwayne Washington ($649,000), Tion Green ($557,000)

Pending free agents: Zach Zenner

The Lions went into last offseason with a running game that finished 30th in the league and didn't have a single back hit so much as 400 yards on the season. Detroit passed on free agents and draft options to trudge on with a backfield that brass felt was simply injured and stuck behind poor blocking in 2016.

A year later, things are worse more than they are better. The Lions finished dead last in yards per game and yards per carry. The backs mostly stayed healthy, but they still shuffled around, with Ameer Abdullah receiving a late benching. No back hit 600 yards on the year, and the drought of no games with a 100-yard rusher reached a fourth season in a row.

It certainly wasn't all their fault, as the offensive line struggled with injuries and poor chemistry and the run designs got Ron Prince fired the day after the season ended. But general manager Bob Quinn admitted that he overestimated his backs last year and that he will add to the position this time around.

The question is how. This year's free-agent class has a number of strong options, including ones with ties to the Lions coaching staff. Detroit isn't flushed with cash, though, and will have to measure these options up against a draft class that is younger, cheaper and filled with good options.

Some fixes will have to come through free agency for this team, and running backs are cheaper than other spots. Here are some of the intriguing options for Detroit this year:

Jerick McKinnon, 25, Vikings: The Lions hired Jeff Davidson to fix their offensive line, so might they bring in a running back who had some nice success under his old blocking scheme? McKinnon has been itching for a bigger role in Minnesota since he arrived as a third-round pick in 2014. He has a career average of 4.0 yards per carry, though that number was up to 4.9 in the two years Davidson was in town. At 5 feet 9 inches and 205 pounds, McKinnon is another back in the frame of Abdullah and Riddick, and he's only scored seven career touchdowns. But he is slippery and could be an option if Detroit wants to try something different than Abdullah.

Carlos Hyde, 27, 49ers: The Lions hired a former Ohio State guard to draw up blocking schemes for a former Ohio State left tackle, so might they get the guy who once ran behind Decker in Columbus? Hyde is a load at 6 feet and 235 pounds, but he can get rolling downfield in a zone scheme as well as a power one. He has 14 touchdowns the past two years, a career 4.2 yards-per-carry average and added some third-down elements to his game last season when he caught 59 passes. The worry with him has been durability, as he's had some brain injuries and has missed 14 games already, though none came last season. He's 27 already, has some good tread on the tires and a battering running style. He could work quite well as the run-down complement to Riddick, but the concussion risk remains real.

Dion Lewis, 27, Patriots: New England found immense success with Lewis as its run-focused back, so might a legion of former Patriots consider trying it now? Lewis is a microscopic 5 feet 8 inches and 195 pounds, but he's been effective in doses, averaging 4.8 yards a carry in three years with the Patriots. Last year was his first legitimate workload, and he turned out his best campaign yet with 896 yards and five scores on 5.0 yards a carry. Perhaps playing 16 games for once eleviated some of the health concerns for a player so tiny, but those have crippled him every other year, as he's missed a combined 26 games so far. He's a player who has to maintain a lightened work load, but that makes him a more intriguing option for a pass-first team with Riddick to play third downs.

LeGarrette Blount, 31, Eagles: Here's another former Patriots find, this time one who excels in the power settings especially. Blount is 31, and he's no spectacular athlete, which has always muted the enthusiasm from teams on an open market. But two straight Super Bowl champions have found good uses for him, from the league-best 18 touchdowns he scored for New England in 2016 to the 4.4 yards a carry he added in a deep backfield for Philadelphia last season. Quinn and Matt Patricia will know his personality and fit well, and they can decide if he's an upgrade over Green worthy of a signing.

Orleans Darkwa, 26, Giants: Here's a player without connections to the staff but whose profile might keep him under the radar amid the other free agents as well as the options in the draft. Darkwa entered the league as an undrafted free agent out of Tulane, bounced around for a bit and then worked up the Giants depth chart until he had 751 yards and five scores on 4.4 yards per carry last season. That came behind arguably the worst offensive line in the NFC. Perhaps that's good training for running in Detroit these days, but Darkwa's profile looks fairly legit now: He's 5-11, 219 pounds, 26 years old and doesn't have much tread on the tires.

Others to watch: Isaiah Crowell, Jeremy Hill, Frank Gore, DeMarco Murray