LONDON — The 49ers are considering deals to extend the contracts of several young players, and that includes troubled linebacker Aldon Smith, general manager Trent Baalke said Friday.

“That’s the ultimate goal,” Baalke said in a 2﻿1/2-hour sit-down with 49ers beat writers. “At the same time, like every player, there’s a lot of things that go into a long-term decision.”

Smith will miss his fifth straight game Sunday after entering treatment following an alleged drunken driving accident. How Smith responds after his rehabilitation stint will factor into his long-term future with the 49ers, Baalke noted.

“It’s like anything, you’re developing that trust factor again,” Baalke said. “We all understand, including Aldon, that situations like this have to be in the past.”

Baalke insisted that there is no timeline for Smith’s return but that the 49ers expect to meet with him in the coming couple weeks.

“Our ultimate goal hasn’t changed: Help Aldon get back to a place he feels very comfortable and move forward in a very positive manner,” Baalke said. “We’re obviously hopeful (for a return after the Nov. 3 bye). At the same time, we’re prepared for either outcome.”

What must Smith show the 49ers to earn his return? “Progress,” answered Baalke.

Among the players Baalke mentioned for potential contracts are Smith, quarterback Colin Kaepernick, left guard Mike Iupati and cornerback Tarell Brown. Kaepernick and Smith can’t get new contracts until after this season, since they’re third-year veterans. Brown lost out on a $2 million workout bonus before the season, and Baalke stated: “We’re doing our best to make it right.”

In addition to the call on Smith, Baalke knows he’s facing some tough decisions in reshaping the roster over the next two weeks. While a big-time trade seems unlikely, the addition of three players off injured lists is mostly a foregone conclusion.

Wide receiver Mario Manningham, cornerback Eric Wright and defensive tackle Tank Carradine likely will join the 53-man roster by Nov. 5, but not in time for Sunday’s game against Jacksonville, Baalke said.

Wright’s incoming addition to the cornerbacks corps means “these guys are all fighting for positions right now,” Baalke said.

Baalke didn’t say so, but it would seem that Nnamdi Asomugha, a healthy scratch in recent weeks, could be most expendable among that unit.

One bench-warmer who won’t be leaving by Tuesday’s trade deadline is running back LaMichael James.

“We’re not interested in trading LaMichael,” Baalke said. “LaMichael is a key player, and there will be a time, sooner or later, to (contribute).”

In terms of trading for a wideout, such a move is unlikely because of the expected returns of Manningham and eventually Michael Crabtree.

Finding an on-field complement to No. 1 wideout Anquan Boldin has been a struggle, although Baalke took exception to the notion the 49ers haven’t found a No. 2 wideout in recent years.

That said, he’s hoping Manningham will make an impact on a corps that also includes Kyle Williams, Jon Baldwin, Marlon Moore and injured rookie Quinton Patton. Moore was a healthy scratch last game, perhaps indicating he’ll be waived to clear room for Manningham.

Carradine, a second-round draft pick, is coming along well from November’s knee injury and has trimmed down to about 285 pounds, the 49ers’ ideal weight for him.

“We certainly expect him to play a key role moving forward,” Baalke said of Carradine. “How soon? That’s up to the player. He’ll be ready this year. He’s missed a lot of football, and for a rookie, that complicates things.”

As for the 49ers’ 5-2 start, Baalke is especially proud of how the coaches and players have overcome a torrent of adversity. He declined to single out individuals, but it was easy tell how impressed he’s been by Frank Gore and the run-oriented offense.

Baalke also had high praise for Boldin: “Certainly Anquan has proven his worth. There’s no better professional in the NFL than ‘Quan. He’s a leader, a mentor and a great family man. He’s a class act.”

Safety Donte Whitner said the “small sprain” to his knee won’t keep him out Sunday but that he won’t be 100 percent. Whitner didn’t have to risk reinjuring it on a muddy practice field Friday, at least. The 49ers moved their practice site from The Grove in the Hertfordshire countryside to Allianz Park, an artificial-turf field that’s home to Saracens Rugby Club. Whitner and the 49ers (5-2) are prepared, however, for encountering a potential slippery surface at Wembley Stadium, where they’ll face the Jaguars (0-7). “We’ll deal with it and use longer cleats,” Whitner said.

Coach Jim Harbaugh cited two reasons for the 49ers’ move out of The Grove: its practice field was too soggy, and players and coaches planned to go sightseeing Friday afternoon after practice, so Allianz Park brought them halfway closer to London. Harbaugh hoped to descend into Winston Churchill’s war rooms, stating: “That would be one of the highlights of my life.”

The Tennessee Titans’ Akeem Ayers was fined $15,750 for his hit Sunday on Kaepernick that nullified an interception.