SAN FRANCISCO - Ryan Leaf, whose short career has been blemished by a shoulder injury and questionable behavior, pumped his fist in the air triumphantly as teammate Terrell Fletcher crossed the goal line Saturday night.
In his first NFL appearance in 20 months, Leaf led a two-play touchdown drive that ended with Fletcher's 2-yard dash and the San Diego Chargers opened their preseason with a 23-20 victory over the San Francisco 49ers.
After a cameo appearance for starter Jim Harbaugh, Leaf was 7-of-12 passing for 103 yards and a touchdown. But he also had an interception and two fumbles - and two of the turnovers led to 49ers field goals.
''He didn't miss a read, we missed the protections,'' Chargers coach Mike Riley said at the half. ''And that caused a couple of turnovers. I thought he played with a lot of poise for his first time playing in a while.''
After John Carney kicked a 36-yard field goal in the opening series, Leaf's handoff to Fletcher put the Chargers up 10-0, a score punctuated by his pumping fist.
Leaf added a 5-yard scoring pass to Reggie Jones midway through the second quarter, putting the Chargers up 17-0.
Ronney Jenkins added an 86-yard kickoff return just before halftime to give the Chargers a 23-6 lead at the break.
James Tuthill kicked a 33-yard field goal and Wade Richey added a 47-yarder for the 49ers in the first half.
San Francisco quarterback Rick Mirer narrowed the margin to 23-13 with an 8-yard touchdown run in the third quarter. Jonas Lewis ran four yards for a touchdown midway through the fourth quarter.
Leaf, San Diego's highly touted top draft pick in the 1998 draft, had a disastrous rookie season, benched after nine starts with just two touchdowns and 15 interceptions.
Last season, Leaf injured his shoulder 20 minutes into his first practice and needed surgery. The injury, plus a four-week suspension for cursing at then-general manager Bobby Beathard, ended his second year. He had another surgery earlier this year.
''I took a couple of shots, tested my shoulder,'' Leaf said. That's all we wanted to do was test it. And it came through.''
In addition to cursing at Beathard, Leaf has been accused of yelling at members of the media and other generally boorish behavior over the course of his short career.
Before Saturday night, Leaf had not played in an NFL game since Dec. 13, 1998.
Raylee Johnson intercepted Jeff Garcia on San Francisco's first series of the game, putting the Chargers on the 49ers 27. Leaf hit Mikhael Ricks with a 25-yard pass, then gave the ball to Fletcher for the touchdown at 7:56.
Leaf is listed as third on the Chargers' depth chart, behind 36-year-old Harbaugh and Moses Moreno, who has made one NFL start.
''I thought Ryan was real aggressive, poised in the pocket and made a lot of good throws,'' Harbaugh said.
Moreno replaced Leaf for the second half.
It was the preseason opener for the Chargers. The 49ers lost their first preseason contest 20-0 to the Patriots in the Hall of Fame game in Canton, Ohio.
Garcia, who took only 13 snaps in the Hall of Fame game, completed 5-of-7 passes for 26 yards before being replaced by Mirer, who signed with the 49ers before training camp. Mirer completed 12 of 23 passes for 103 yards and one touchdown.
The 49ers were without at least 10 players because of injuries, including veteran defensive end Junior Bryant, who had arthroscopic surgery on his left shoulder, and linebacker Ken Norton, who has a sore back.
Niners wide receiver J.J. Stokes left in the first half with a hamstring injury.