We were promised five first-round quarterbacks, and we got five first-round quarterbacks. The 2018 NFL draft was just the third of the modern era to see five or more quarterbacks come off the board in the opening round, and while there are no guarantees about their chances of succeeding, history suggests that two or three of these quarterbacks will turn into franchise passers.

In looking at why quarterbacks from the past struggled, I found that teams were routinely either disingenuous or naive about how long rookies would sit before being inserted into the starting lineup. Take the case of Blake Bortles, who had mechanical issues in college at UCF. When the Jaguars drafted Bortles with the No. 3 pick in 2014, they suggested they would give Bortles a redshirt year to rebuild his mechanics. That redshirt "year" lasted until the second half of Week 3, when the Jags inserted Bortles into the lineup for a struggling Chad Henne. Bortles hasn't left the starting lineup since, although his mechanics have ranged from effective to downright disastrous over that time.

Teams don't always regret moving up a time frame. The Eagles planned to redshirt Carson Wentz during the 2016 season, only to trade Sam Bradford to the Vikings at the end of training camp and insert Wentz into the lineup after just 24 mediocre preseason pass attempts. Wentz looked great early before taking his lumps during an uneven rookie campaign, but by his sophomore season Wentz blossomed into an MVP candidate.

In most cases, teams talk about caution in April and then can't wait to play with their new toy by the end of September. Let's be more realistic. We can't foresee injuries or trades like Philly's Bradford swap, but let's estimate the time frame for each of the five first-round quarterbacks given their landing spots and the quarterback depth chart. When are they likely to see the field? And, perhaps more important, when should they be inserted into the starting lineup? In draft order ...

Baker Mayfield, Cleveland Browns

When he should be inserted into the lineup: Week 12. When the Browns traded for Tyrod Taylor, they were going after a quarterback who could help them be competitive in the short term while coach Hue Jackson and offensive coordinator Todd Haley worked on developing the first overall pick in the background. Taylor is an unrestricted free agent after this season, so the Browns won't have much of a reason to be loyal to their current starter beyond keeping his market value high in free agency as a possible compensatory pick.

If general manager John Dorsey gets a significant offer for Taylor before the season or even at the trade deadline, it would hardly be crazy to ship the former Bills starter to a new team. Assuming that Taylor sticks around, though, the right time to make a move with Mayfield would be after the Week 11 bye. Taylor and the Browns should have done enough by that point to distance themselves from the 1-31 stretch of 2016-17, and with six games to go, the Browns would have enough time to get Mayfield's feet wet and evaluate what he needs to improve in advance of being the full-time starter in 2019.

The only concern here is the schedule, given that the Browns would be facing road games against the Broncos, Ravens and Texans to go with a home game against the Panthers. Unless the Browns want to sit Mayfield for an entire season, though, he's likely going to end up facing some of those tough matchups during his debut campaign.

When he will be inserted into the lineup: Second half of Week 8. Unless the Browns get off to a hot start and look like a viable playoff contender, it's unlikely that Jackson & Co. will be able to resist the urge to push their franchise passer into the lineup by the bye week. It would hardly be a surprise to see the Browns install some elements of the Lincoln Riley attack that Mayfield excelled with at Oklahoma, both for Taylor and for the reigning Heisman Trophy winner.

Given Jackson's impatience with his quarterbacks, it makes sense that we'll see Mayfield enter into the game during the second half of a blowout. The most likely loss on Cleveland's schedule is in Week 8, when the Browns travel to play the Steelers in Pittsburgh. Giving Mayfield the second half of the game there also would make it easier to push him into the starting lineup for a pair of subsequent home games against the Chiefs and Falcons, neither of whom had above-average pass defenses last season, before that Week 11 bye.

play 0:38 Mayfield happy to share his story with Browns during draft process Baker Mayfield explains what he is most anxious to prove and what he enjoyed about the draft process.

Sam Darnold, New York Jets

When he should be inserted into the lineup: Week 1, or not until 2019. Let me explain. The biggest concern about Darnold as he heads into the league is his elongated throwing motion, although the Jets obviously don't think it's going to be a huge hindrance. Darnold didn't make any changes to his throwing motion during the pre-draft process, but the Jets might decide they want to shorten Darnold's delivery behind what is likely to be one of the league's lesser offensive lines.

If the Jets want to keep Darnold's motion as is, there's no real reason to stick Josh McCown in the lineup for some indeterminate amount of time before handing the job over to Darnold. Gang Green isn't likely to be competing for a playoff spot, and giving Darnold a full season to adjust his internal clock to the speed of NFL pass-rushers would be far more valuable -- especially considering Darnold's propensity for turning the ball over during his time at USC (22 turnovers in 2017).

Alternately, if the Jets do want to work on Darnold's mechanics and reconstruct him as a passer, it's better to give offensive coordinator Jeremy Bates a full season to work on the third overall pick without worrying about Darnold coming in as relief for McCown. Of course, if the Jets do struggle, the duo of coach Todd Bowles and GM Mike Maccagnan will likely want to show off what Darnold can do before ownership decides on their future with the team, so that's an unlikely proposition.

When he will be inserted into the lineup: After McCown gets hurt. The Jets brought in McCown to serve as a placeholder in 2017 and got an impressive season, both in terms of performance and health. After suffering injuries in September during the 2014, 2015 and 2016 seasons, the 38-year-old veteran stuck in the lineup all the way until Week 13 before going down with a broken hand.

Bowles understandably hopes that McCown will help develop Darnold during the season, but given McCown's injury history, it's likely that McCown will be forced off the field during the first half of the campaign. Once that happens, the Jets should push Darnold into the lineup ahead of Teddy Bridgewater and Christian Hackenberg, neither of whom are locks to even make the roster.

If McCown does stay healthy -- or the Jets get impatient in the nation's biggest media market -- it wouldn't be a shock to see Darnold make his first start during the Jets' three-game homestand in October, likely against the middling pass defense of the Colts in Week 6.

Without a seasoned starter ahead of him, Josh Allen could see the field sooner rather than later. AP Photo/Jeffrey T. Barnes

Josh Allen, Buffalo Bills

When he should be inserted into the lineup: Week 13. Allen is the biggest boom-or-bust quarterback in this class. While the Bills don't necessarily need to fix his mechanics, Allen will need to improve his comfort level in the pocket and patience in going through his progressions before making throws in places where only his receivers can bring in the football. That's going to take both time and meaningful NFL reps.

Allen might end up looking great in the preseason -- as Bortles did back in 2014 -- but that shouldn't influence the Bills into pushing their top pick into the lineup early. Allen shouldn't be put under pressure to win games now as the starting quarterback for a team that made the playoffs a year ago. The Bills also have major concerns on the interior of their offensive line after losing Eric Wood to retirement and Richie Incognito to occasional retirement, problems they'll want to find a resolution to before throwing Allen to the wolves.

The Bills have a Week 11 bye, but they come back in Week 12 with a home game against the Jaguars, who attacked quarterbacks like actual wolves last season. Inserting Allen into the starting lineup for the Week 13 trip to Miami leaves Buffalo with five games to go, none of which is likely to come against a team with an above-average pass defense. Three of those games are at home. If the Bills are out of playoff contention, Week 13 would be the optimal time to get Allen on the field under relatively friendly conditions.

When he will be inserted into the lineup: Week 5. The Bills are perhaps the most likely team in the league to regress in 2018, given that their 9-7 record was built upon an unsustainable 6-2 record in games decided by seven points or fewer. They also start the season with a brutally tough slate, including road games against the Ravens, Vikings and Packers and a home game against the Chargers, who beat the Nathan Peterman-led Bills by 30 points last season. AJ McCarron is likely to begin the year as Buffalo's starter, but if the Bills get off to a 1-3 or 0-4 start, Allen could be in the lineup by the time the Bills get into their three-game stretch against the AFC South.

Josh Rosen, Arizona Cardinals

When he should be inserted into the lineup: When Sam Bradford gets hurt. Many observers regarded Rosen as the most pro-ready quarterback in this draft class by virtue of playing in a West Coast scheme under Jim Mora Jr. at UCLA. The concerns about Rosen are more about his arm strength and intangibles, problems that aren't going to be fixed if Rosen sits on the sideline.

The Cardinals already have committed a minimum of $15 million to Bradford, a figure that will likely rise to $20 million unless Arizona trades him before or during the season. If a team offers a first-round pick for Bradford, as was the case with the Vikings before the 2016 season, the Cards would be smart to give that serious consideration. The chances of that happening, though, are relatively slim.

Given Bradford's track record, everyone expects him to get injured at some point during the 2018 season. He has completed just three healthy seasons in his eight pro campaigns and has missed 37.5 percent of possible games since entering the league as the first overall pick. The simplest projection suggests that Bradford will suit up for 10 games in 2018. The first time he's hurt, though, the Cardinals should use the opportunity to replace him with the 10th overall pick.

When he will be inserted into the lineup: When Bradford gets hurt. This one seems pretty straightforward. Even if the Cardinals are competitive in a tough NFC West, Arizona is likely to turn things over to Rosen once Bradford is unable to play. The Cardinals also have Mike Glennon on the roster, but putting the former Bears starter into the lineup ahead of Rosen would be, as the UCLA product would put it, a mistake.

play 1:10 Riddick says Jackson to Ravens is best fit of QBs Louis Riddick says Ravens OC Marty Mornhinweg is the perfect match for Lamar Jackson.

Lamar Jackson, Baltimore Ravens

When he should be inserted into the lineup: Week 1, 2019. Jackson is more pro-ready than some observers might have you believe, given that he was playing in an NFL offense for Bobby Petrino at Louisville. Just about everyone agrees that Jackson needs to work on his footwork inside the pocket, which one hopes should improve the accuracy of a quarterback who completed 57 percent of his passes at Louisville.

In the short term, Jackson should have a part-time role as a dual-threat quarterback, where he should be absolutely terrifying against tired defenses for a snap or a series. With a veteran Ravens team desperate to make it back to the playoffs, though, Joe Flacco likely offers a higher floor than a developing Jackson. Giving him a year of remedial work would allow Baltimore to rebuild Jackson's footwork while simultaneously allowing teams to prep for the 2016 Heisman winner by giving him a few snaps per game.

The Ravens can move on from Flacco and free up $18.5 million under their 2019 cap by designating the former Super Bowl winner as a post-June 1 release, so unless Flacco excels under the threat of Jackson this season, the 2019 offseason seems like the logical time for John Harbaugh & Co. to make the change.

When he will be inserted into the lineup: Week 1, 2019. The Ravens moving up to draft Jackson shows just how exhausted this franchise is of the Flacco era, a run that has yielded just one playoff win since that Super Bowl victory following the 2012 season. It's also difficult to see Flacco playing poorly enough for Harbaugh to make an in-season change. Flacco's relatively clean injury history -- nine healthy seasons with a 10th ended by a torn ACL -- also makes it unlikely that the job will open up for Jackson.

It's always possible that Jackson excels for a few snaps and the Ravens turn to him in the middle of a losing streak. Baltimore does have a stretch with three consecutive road games and four away games in five weeks from Weeks 4-8, followed by a home game against the Steelers. If they hit their bye with a sub-.500 record, maybe Harbaugh makes a change and hopes Jackson somehow saves Baltimore's season. Otherwise, the most plausible time for a change is next March.