NASHVILLE, Tenn. --bThe Tennessee Titans got Jake Locker back.
Unfortunately, the quarterback couldn't stop his teammates from making mistakes and added one himself with his first interception this season.
Locker threw for 326 yards and two touchdowns in his first game back after spraining his right hip and knee, but the Titans were outplayed Sunday, losing 31-17 to the San Francisco 49ers.
Now they have lost three straight and need some corrections in their bye week.
''We're going to look at where changes are necessary and make them,'' Titans coach Mike Munchak said.
The Titans (3-4) committed 10 penalties for 100 yards, including an unnecessary roughness call that wiped out an interception.
The Titans pulled within 24-10 when Tommie Campbell blocked an opponent into Darius Reynaud, who fumbled a punt that Kassim Osgood recovered in the end zone for the clinching TD.
But the Titans also started at their own 11 and 9 late in the second quarter off Reynaud's kickoff returns, the same returner who opened the season taking a safety stepping on the goal line in Pittsburgh.
''That's something that can't happen,'' Munchak said. ''It is definitely a concern and what we'll do, we'll wait and see.
''Again ... there's a few areas where we're going to have to take a good look at and make sure we're doing what's best for this football team to win. ... We still have a lot of football to play. This thing can be dramatically different once we get an opportunity to play some other teams. So you can't panic.''
The Titans started Locker just three weeks after being taken by ambulance to a local hospital.
Wearing a brace on his right knee, he ran three times for 29 yards and also was sacked three times. Locker said he felt good and only wishes he had one throw back, which was picked off by Tramaine Brock.
That mistake along with the penalties and dropped passes had the Titans looking at their first shutout in the 150th game all-time at LP Field before a fourth-quarter rally fizzled amid more mistakes.
''We found ways to stall drives out,'' Locker said. ''I didn't think it was really us getting going. We've got to find ways to do that.''
Tennessee trailed 17-0 at halftime and 24-0 through three quarters. Locker's scramble set up a field goal by Rob Bironas, then he dumped off a pass to Chris Johnson that the running back took 66 yards weaving through the 49ers for a touchdown. Locker capped the scoring with a 26-yard TD pass to Delanie Walker.
That score pulled them within 31-17 with 3:17 left, and Munchak went for an onside kick that he didn't try in losing 20-13 at Seattle a week ago. But the 10th penalty didn't help as rookie Daimion Stafford was offside, and the 49ers recovered before running out the clock.
''It's really frustrating just looking at it because the defense came out playing well, and we just kept doing stuff to mess up the drives,'' Johnson said. ''We got holding calls, dropped balls, etc. Anytime you're playing a team like that when you get opportunities you have to drive down the field and put points on the board.''
The 49ers (5-2) won their fourth straight and look like the team that went to the Super Bowl last season.
The Titans outgained the 49ers 368-349 in total offense only because of a frantic fourth quarter as they tried to rally.
San Francisco still had a big edge in time of possession, holding the ball for more than 35 minutes, including the third quarter when the 49ers played keepaway for more than 11 minutes. Frank Gore capped the opening drive of the third with his second TD for a 24-0 lead.
Colin Kaepernick threw for 199 yards and ran for a TD as well as the 49ers started their longest road trip this season with a win before heading to London.
''I don't know how you define midseason form, but we have strung together a few wins and we feel pretty good about what we're doing right now,'' Kaepernick said.
NOTES: Brock has three interceptions in three games. ... The 49ers lead this series 8-5. ... The Titans had a video tribute to the late Bum Phillips and a moment of silence before the coin toss. Phillips coached this franchise to two AFC championship game appearances in the late 1970s as the then-Houston Oilers. ... Johnson has three TD catches of 66 yards or longer and 11 TDs of 66 yards or longer in his career.