Few are expecting any blockbuster trades before Tuesday's deadline.
Since the new collective bargaining agreement was signed in 2011, teams have tried to avoid trades involving anything higher than a fourth-round pick. Even though the number of trades has increased by 14 percent this year, most of the deals have involved draft choices between Rounds 5 and 7 or future picks in the same range.
That doesn't mean teams can't pick up great players, but the price might be too high for most. Nevertheless, there have been many in-season blockbusters. Here are the top 10:
1. Halfback Herschel Walker from Dallas Cowboys to Minnesota Vikings in 1989: Six weeks into the 1989 season, coach Jimmy Johnson realized his 0-5 Cowboys were going nowhere fast. He saw a team that was old and slow. In perhaps the boldest trade in NFL history, Johnson shipped his best player (Walker), two third-round choices, a fifth-rounder and a 10th-rounder to Minnesota for five veteran players, three first-round picks, three second-round picks, a third-rounder and a sixth-rounder.
The Vikings made the playoffs with Walker that year but had 6-10 and 8-8 records the next two seasons before letting him go. Walker didn't have a 1,000-yard rushing season during his short stay in Minnesota.
Johnson developed a dynasty with the trade. He maneuvered up and down the draft boards with all the riches from the Walker trade and ended up with top players such as halfback Emmitt Smith, safety Darren Woodson, defensive tackle Russell Maryland and cornerback Kevin Smith. From 1992 through 1995, the Cowboys won three Super Bowls.
2. Cornerback Michael Haynes from New England Patriots to Los Angeles Raiders in 1983: Haynes wanted out of New England. His agent, "Hold 'em out'' Howard Slusher, held Haynes out into the season and sued the league. As a settlement, the Patriots accepted a 1984 first-round choice and a 1985 third-rounder for the 30-year-old Haynes.
This trade epitomized Al Davis' commitment to excellence. Haynes, a Hall of Fame cornerback, paired up with Lester Hayes to become one of the greatest man-to-man cornerback tandems in NFL history. The trade helped put the Raiders over the top; they won the Super Bowl that season. Two more playoff seasons followed. The Patriots hovered around .500 in 1983 and 1984.
3. Quarterback John Hadl from Los Angeles Rams to Green Bay Packers in 1974: Packers coach Dan Devine was desperate for a quarterback acquisition. The Packers were 3-3 and needed a spark. He toyed with the idea of bidding for Archie Manning. He threw everything on the table to get the 34-year-old Hadl from the Los Angeles Rams. It cost the Packers first-, second- and third-round picks in 1975 and a No. 1 and No. 2 in 1976.
It was one of the worst trades in NFL history. Hadl completed only 48.4 percent of his passes, and the Packers finished 6-8. Devine was fired after the season. Hadl lasted only one more year. In his 22 games as a Packer, Hadl threw nine touchdowns and had 29 interceptions.
4. Halfback Eric Dickerson from Los Angeles Rams to Indianapolis Colts in 1987: After gaining 6,959 yards in his first four seasons, Dickerson balked at the Rams' contract extension offer of $975,000, which represented a meager $293,000 raise. Dickerson sulked and his attitude wasn't great. So the Rams shopped him.
After moving from Baltimore to Indianapolis, the Colts were 12-36 and needed something to energize the franchise. The Colts put together a megatrade to acquire Dickerson. The trade was so complicated, the Colts had to employ a third team -- Buffalo -- which ended up getting Colts linebacker Cornelius Bennett.
The trade happened on Halloween, and all of a sudden the Colts were a winning team. Dickerson gained 1,011 yards as the Colts finished 9-6 and won the AFC East. The Rams finished that season 6-9 but used the draft choices they received to put together two playoff seasons. This trade was win-win-win for all three franchises.
5. Quarterback Bobby Layne from Detroit Lions to Pittsburgh Steelers in 1958: Layne could party hard off the field but was a winner on it. He won three championships during his eight years in Detroit. But in the 1958 preseason, Layne split playing time with quarterback Tobin Rote, and two games into the season the Lions traded Layne to Pittsburgh for quarterback Earl Morrall, a first-round pick in 1959 and a second-rounder in 1960.
As the legend goes, Layne said, "The Lions will not win for 50 years''; although no writer ever published the direct quote. Layne never turned the then-losing Steelers into a playoff team, but the Lions have won only one playoff game since that trade. Detroit has made the playoffs 11 times since 1958 but hasn't reached a Super Bowl, causing some to call it the Curse of Bobby Layne Trade.
6. Wide receiver Roy Williams from Detroit Lions to Dallas Cowboys in 2008: The Lions were in the early stages of a 0-16 season. Cowboys owner Jerry Jones called trying to acquire the Lions' best receiver, Williams. The cost was a first-, third- and sixth-round pick in 2009. Jones later gave Williams a $54 million contract extension.
Jones thought he acquired a No. 1 receiver, but he acquired a receiver who never caught more than 38 passes in season as a Cowboy. The Lions used the first-round pick acquired from Dallas on tight end Brandon Pettigrew in the same draft that they selected quarterback Matthew Stafford. The trade helped to rebuild the Lions. The Cowboys didn't win a playoff game during the three-and-a-half seasons Williams was with them.
7. Halfback Marshawn Lynch from Buffalo Bills to Seattle Seahawks in 2010: As a Bill, Lynch's numbers were dropping in 2009 and 2010. After rushing for 2,151 yards during his first two seasons, Lynch rushed for 450 in 2009 and had 164 in his first four games in 2010.
First-year Seahawks coach Pete Carroll was looking for a power back to carry his offense. The Bills accepted a fourth-round pick in 2011 and a fifth-rounder in 2012. For the Seahawks, Lynch was as effective as Earl Campbell was for the Houston Oilers. By going Beast Mode, Lynch rushed for 5,357 yards from 2011 through 2014 and has been one of the top three backs in football.
8. Quarterback Carson Palmer from Cincinnati Bengals to the Oakland Raiders in 2011: Palmer got tired of losing in Cincinnati, so he retired. The Raiders felt he could turn around their years of losing and gave up a first-round pick in 2012 and a second-rounder in 2013. The Raiders were right -- and wrong.
They were wrong in thinking he could improve the Raiders. His record as a Raider was 8-19. They were right in thinking he could carry a franchise to the playoffs. Palmer has turned the Cardinals into a playoff team after the Raiders dumped him for a swap of sixth-rounders and a seventh-rounder. The Bengals ended up getting cornerback Dre Kirkpatrick and halfback Giovani Bernard with the two Raiders picks.
9. Halfback Trent Richardson from Cleveland Browns to Colts in 2013: Richardson was a first-round bust for the Browns. He averaged 3.6 yards a carry as a rookie, and Browns management jumped at the chance of getting a 2014 first-rounder from the Colts.
Although Richardson was the third pick in the 2012 draft, the Browns traded him after only 17 games. The Colts were looking for a back who could rush for 100 yards a game to make life easier for quarterback Andrew Luck. Richardson played 29 games for the Colts, rushed for 917 yards and averaged 3.1 yards a carry.
10. Wide receiver Deion Branch from Patriots to Seahawks in 2006: Branch was in a contract dispute with the Patriots. He was upset the Patriots weren't offering to extend his contract, which was in its final year. Patriots coach Bill Belichick didn't flinch when the Seahawks offered a first-round pick in 2007 for Branch.
The move failed for Seattle. Branch never had a 1,000-yard year during his five seasons in Seattle. In fact, he had only one season in which he had more than 417 yards; he tallied 661 yards in 2007. After the Seahawks gave up on him, he went back to New England and had better seasons than he did in Seattle.