Stafford, Quinn have impressed early

As the NFL moves into June -- only eight weeks until training camps open -- the outcome of several quarterback battles is still far from clear.

Lions coach Jim Schwartz is hinting an arms race may be developing between Matthew Stafford and Daunte Culpepper. Is there really a chance Chris Simms could beat out Kyle Orton in Denver? While the Vikings wait to see if Brett Favre is going to come out of retirement, Tarvaris Jackson and Sage Rosenfels were splitting reps in this past weekend's minicamp.

In a league that demands stability at quarterback, more questions are surfacing than are being answered. With that in mind, let's take a look at what we have learned so far.

Detroit Lions: Every day in organized team activities or minicamp, Stafford unleashes two or three incredible throws that make coaches and players go "wow." Over the weekend, Schwartz suggested a race is starting. The organization had better watch the clock. From what has been seen in Stafford's first month with the team, it's inevitable he will be the starter. The question is when. Schwartz marvels at Stafford's release and how well he's picking up the offense. San Francisco 49ers coach Mike Singletary said it best recently when he observed that quarterback controversies take care of themselves in the locker room because the players can judge the best quarterback. The problem facing the Lions is the start of the season. They are on a 17-game losing streak and have a tough start to their schedule, with games at New Orleans and Chicago and at home against Minnesota, Washington and Pittsburgh in the first five weeks. If they put Stafford out there for a five- or six-game losing streak, he will forever be linked with the ineptitude of the past. Culpepper still holds the edge, but the margin is narrowing.

Cleveland Browns: Brady Quinn might not be opening a huge lead on Derek Anderson, but he's the favorite. Coach Eric Mangini learned two things this offseason: Quinn has better trade value and a great work ethic. The Browns could have secured a first-round pick for Quinn if they had wished. But Anderson, for whatever reason, never really captured anyone's interest despite having a strong arm and a Pro Bowl season in 2007. Quinn has committed himself to the weight room and the tape machine; he's always working. Heck, if he were a rookie, he might have driven Mangini's bus 10 hours to participate in the coach's football camp for kids in Hartford, Conn. Quinn is the clubhouse leader.

Denver Broncos: Maybe it's me, but I don't buy the idea that Simms is making a serious run at Orton's starting job. This isn't a knock on Simms. It would be more of a knock on coach Josh McDaniels if it happens. Orton was McDaniels' handpicked replacement for Jay Cutler, who is more talented than Orton. If Orton loses his job to a left-handed quarterback, the move would devalue the 2008 growth of the offensive line. Ryan Clady established himself as one of the league's best young left tackles in 2008. If Simms wins the job, Clady would either have to switch positions to protect Simms' blindside or be a less valuable blocker at left tackle. Advantage, Orton.

San Francisco 49ers: Alex Smith knew he had a huge hill to climb to win back the starting job after not throwing a football in a regular-season game last year. Smith seems to be recovered from shoulder surgery. The bigger problem is Shaun Hill. He just seems to be a more comfortable fit in the 49ers' offense, which will be geared more to running than it has been in the past couple of years. Hill has been running the first team for the entire offseason. The fact that Hill was part of a winning stretch at the end of last season for Singletary will make it difficult for Smith to unseat him. Barring a surprise, Hill will be the 49ers' starter.

Tampa Bay Buccaneers: This is a great horse race. Luke McCown still holds the lead and may come away with the job, but Byron Leftwich is catching up. Leftwich continues to learn the offense and impress coaches with his arm strength and ability to lead a huddle. But don't count out McCown's competitiveness in this process. He hasn't backed down from the challenge so far and hasn't made any missteps. In the end, you would think that Leftwich's experience as a starting quarterback would win out. Everyone probably will have to wait until the preseason games to get a final answer. In the meantime, the coaching staff is working feverishly with Josh Freeman, the quarterback of the future. Slight edge in this one to McCown; but Luke, don't look over your shoulder.

Oakland Raiders: It would be an upset for owner/GM Al Davis to allow coach Tom Cable to start Jeff Garcia over JaMarcus Russell because Davis has so much faith in Russell's abilities. Still, Russell's accuracy hasn't shown much improvement. He has had some bad days and some worse days, but he's still the starter and should be. Garcia is the insurance policy. Garcia shows great leadership in pulling an offense together, but he can't be too eager. This isn't an open competition. The stakes are too high. If Garcia beats out Russell, then Davis would be admitting he made a mistake drafting Russell with the first overall pick in the 2007 draft. Al doesn't like admitting mistakes, so Russell remains the starter.

Minnesota Vikings: Until the Vikings give the No. 4 to Brett Favre, Jackson is the starter. Coach Brad Childress believes in him and that means everything. Even though Jackson and Rosenfels both have worked with the first team, Jackson was the quarterback with the first team in the first practice. It's Jackson's job to lose. Last year, he lost the job to Gus Frerotte and then had to wait until Frerotte got hurt to win back the job. Some people in the organization like Rosenfels more than Jackson, but the coach likes Jackson. It will be Jackson.

New York Jets: Under the circumstances, Kellen Clemens might be the most invisible quarterback in the league. Offensive coordinator Brian Schottenheimer said Clemens is the leading candidate to be the starter, but everyone is talking up rookie Mark Sanchez. Sanchez made more news during a bad week of throwing a couple of weeks ago than Clemens has at any time this offseason. This situation isn't like the one in Detroit, though. The Jets have a better team than the Lions, and the offense has the blockers and runners to make it easier for a rookie quarterback to make the transition into the starting role. Everything will sort itself out in the preseason, but it would be an upset if Sanchez doesn't eventually get the starting nod for opening day. Clemens has the shaky lead for now, but it may not be for long.

John Clayton, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com.