Scouts Buzz: Can career backup save Mike Nolan in San Francisco?

O'Sullivan, a sixth-round pick of the New Orleans Saints in 2002, has apparently beaten out incumbents Alex Smith and Shaun Hill for the role after entering training camp as a long shot.

"It's not a surprising development," said an NFC scout. "O'Sullivan is a smart, athletic and talented player. He may get a little careless with the ball, but he has all of the tools to be a starter in our league."

Although O'Sullivan's numbers have not been spectacular during the preseason (13 of 25 for 225 yards with one touchdown and two interceptions), the 49ers' offense looks better under his guidance. His surprising surge up the depth chart is due to his knowledge of offensive coordinator Mike Martz's complex system, which requires the quarterback to instinctively deliver passes into open areas while trusting receivers to get to the predetermined spots. While this concept is also used in other offensive systems, Martz raises the ante by featuring square-ins and other crossing routes. With the majority of the passing game executed over the middle of the field, the quarterback must have a great feel for anticipating the open windows in coverage.

"Martz's offense requires the ball to come out on time because quarterbacks are instructed to throw the ball to a spot," said an NFC scout. "If there is any indecision in the quarterback's mind, the timing of the route will be thrown off, and it will lead to incomplete passes or interceptions."

After spending a season working under Martz in Detroit as Jon Kitna's backup, O'Sullivan understands the impeccable timing that is required for the offense to run efficiently, and his success guiding the 49ers' is due to his willingness to quickly find the second and third option in the progression. While Smith and Hill wait in the pocket for the first read to come open, O'Sullivan comes off the primary quickly when it doesn't appear to open up immediately. Thus, the defense is forced to defend more of the field when the six-year veteran is under center.

"He [O'Sullivan] is a pretty bright guy," said an NFC scout. "He entered the league as a bit of a gunslinger, but he has toned down his game and become a more complete player."

But there are still major questions surrounding the insertion of O'Sullivan in the starting lineup. He has 26 career pass attempts in five games. While inexperience doesn't mean that O'Sullivan is destined to fail, the fact that he is currently with his eighth franchise (Saints, Packers, Vikings, Patriots, Bears, Panthers, Lions and 49ers) is a little disturbing. The NFL's lack of quality quarterbacks has been well documented, so it is quite surprising that one of those franchises was not able to identify O'Sullivan's potential as a future starter. In fact, the quarterback-hungry Bears declined to bring O'Sullivan to training camp after watching him win NFL Europa's Offensive Co-MVP award while guiding the Frankfurt Galaxy to the World Bowl in 2007. (O'Sullivan posted a league-leading 103.1 passer rating while completing 160 of 235 passes for 1,997 yards with 15 touchdowns and seven interceptions.)

However, 49ers' followers should not be discouraged by O'Sullivan taking the reins of the offense. Martz transformed unheralded Kurt Warner and Marc Bulger into Pro Bowl quarterbacks, and Kitna enjoyed the best seasons of his career under Martz's tutelage. Thus, it's not out of the realm of possibility that O'Sullivan blossoms into a solid player under Martz's watch.

With his job on the line, Mike Nolan can only hope that Martz has discovered another hidden gem.

After laboring through an injury-plagued rookie season, Lions receiver Calvin Johnson appears poised for a breakout season. The former No. 2 overall pick has been outstanding during the preseason, flashing the talent that had most scouts proclaiming him the "best football player" in the 2007 NFL Draft.

"He is an absolute freak on the field," said an NFC scout. "It's so rare to find a guy with his combination of size, speed and skills."

While Johnson didn't make the sudden impact most predicted, that he finished the season with 48 receptions for 756 yards and four touchdowns in 10 starts (second among all rookies) is impressive considering he played the majority of the season with a nagging back injury. But bolstered by a return to good health, Johnson has been a dominant player during the preseason (seven receptions for 154 yards and one touchdown), and appears ready to become a key playmaker opposite Pro Bowl wideout Roy Williams.

"I think he's making that leap that you see second-year players make from their first year," teammate Brian Kelly told MLive.com earlier this summer. "He's learning the offense and it's just about making plays at this point.

New offensive coordinator Jim Colletto has also helped Johnson become a dominant force by utilizing more two-back sets and a power running game. Defenses are forced to drop a safety into the box to defend the more-balanced offense, and Johnson has been able to feast on single coverage on the outside by using his imposing size (6-5, 240 pounds) and speed. Plus, the presence of Williams prevents teams from consistently rolling double coverage to Johnson's side.

"He is beginning to come into his own," said an NFC scout. "I don't think that it would surprise anyone to see him wind up in the Pro Bowl this season."

The Falcons finally granted veteran receiver Joe Horn his release, but he may find it difficult to land in a situation better than the one he left. Although Horn has earned four Pro Bowl berths in his 13-year career, his skills and production have steadily declined in the past three seasons. Horn only averaged 38 receptions and 525 receiving yards since his last Pro Bowl season in 2004, and is coming off a 27-catch season in which he averaged nine yards per catch.

"He's definitely not the player he was in his prime," said an AFC personnel director. "He still has some straight-line speed, but he is no longer explosive and is unable to get separation from defenders on a consistent basis."

Despite that assessment, Horn and his representatives believe there is a market for a 36-year old receiver, who hasn't played a full season in three years. They cite Jacksonville, Seattle, Tennessee and Dallas as possible destinations.

"Joe has been so productive," Horn's agent, Ralph Vitolo, told the Associated Press. "Somebody like Joe and a team with a need should be a perfect fit."

While it is true that there are several teams with a need for a solid complementary receiver, Horn is a No. 4 receiver at this stage, and a team is unlikely to pay significant money to a receiver clearly on the downside of his career. Though the Falcons are on the hook for Horn's $2.5 million salary this season, teams are not likely to make an immediate play for Horn. With the first cutdown day less than a week away, teams will scour the waiver wire for younger veterans before thinking about signing Horn.

"All teams would like to add a veteran to mentor their young guys," said an NFC personnel director. "But you hope that player still has some upside and ability. I'm not sure that [Joe] brings those things to the table at this point."

Horn desperately wanted a chance to play for a contender, but time will tell if he has talked his way out of the best situation for him.