TORONTO -- Defensive help is on the way to Toronto FC, in the form of a new assistant coach.

Manager Greg Vanney says he is adding a coach who was one of his mentors when it came to defending.

"Obviously we have a lot of young defenders who are talented but they need to progress," Vanney said after practice Wednesday. "Hopefully he'll be in Sunday or Monday of next week

"He'll really really start to push on our defensive group. But he's also been around the game long enough that he understands both sides of the ball. But I really want us to shore up our defensive backline. And then I think we have the quality in attack where we can make a difference."

He declined to identify the coach until everything was finalized.

Vanney also had good news on the Jermain Defoe front, saying the injured striker could be back in town earlier than the original Sept. 20 date to continue his rehab from a groin injury. There is no word on when Defoe, who is currently in England, might return to action, however.

The 31-year-old striker has missed nine games this season (eight through injury and one by suspension) but still leads Toronto in scoring with 11 goals.

Toronto (9-11-6) hopes to end a three-game losing and goalless streak when it visits the Chicago Fire (5-7-14) on Saturday. Toronto has won just three of its last 15 games (3-7-5) and fell from fourth to seventh last weekend in the Eastern Conference standings. The top five make the playoffs.

Going into play Wednesday, Toronto ranked 14th in the league in goals-against (1.62 per game).

Injuries, suspension and lack of depth have cost the team in defence with centre back Steven Caldwell and fullbacks Justin Morrow and Mark Bloom missing 21 games between them. That has forced others to play out of position and put youngsters Doneil Henry and Nick Hagglund in the firing line.

Toronto's training room is beginning to empty -- the team has lost players to injury for a combined 82 games this season -- but still has work to do.

Caldwell (quad) is progressing but still "very questionable" for the weekend, Vanney said. Midfielder Jonathan Osorio (leg muscle) was described as day to day. Defender-midfielder Bradley Orr (toe) did not take part in practice with the main squad Wednesday but is expected to be available this weekend.

Vanney said the team is looking at shifting fullback Justin Morrow to centre back with Caldwell and Bradley Orr both nursing injuries.

"It's definitely something that we've talked about," said Vanney. "It's not his natural position but obviously he's done it in the past a little bit. It's definitely something that's crossed our mind and we thought about it. I can't say we've made a decision either way but it's definitely an option."

In the part of practice open to reporters Wednesday, Bloom and Warren Creavalle played fullback in an attacking drill.

As for adding a new player, Vanney said "if it's the right fit we're definitely looking. But nothing's been determined yet."

With the international transfer window closed, Toronto would have to acquire new talent via an MLS trade or look for a player out of contract.