Union sign Olivier Mbaizo, Cameroon-born defender, from Bethlehem Steel

The Union signed 20-year-old Cameroonian defender Olivier Mbaizo to an MLS contract Tuesday after initially signing him to a USL contract with Bethlehem Steel in January.

Mbaizo gives the Union needed depth at outside back. He also gives them some questions to answer.

The biggest is whether manager Jim Curtin thinks he needs a new starting left back after Matthew Real had a rough outing against Orlando City. Mbaizo trained as a left back when he was with the Union in Clearwater, a sign that he might step into that role in games. He has also played at right back, and spent time at that position during the Union's practice Tuesday.

"I'm lucky that I can play in various styles," Mbaizo said in his native French. "I like to play more on the right, but I don't have a problem being on the left."

Benching Real might be harsh, but it might be necessary. While the 18-year-old Drexel Hill native has shown plenty of evidence he'll make it as a pro, he has also shown his limits. In particular, he was right in the middle of both goals that Orlando City scored last Friday, and San Jose's goal a week earlier. And with Fabinho still out because of a torn mensicus, the Union at least need some backup.

"Olivier trained with the Union first team throughout our preseason, and it became clear that he has the potential to immediately contribute at the MLS level," Union sporting director Earnie Stewart said in a statement.

There's a caveat to "immediately," though. Mbaizo hasn't played in an official game for Steel this season after suffering a knee injury during a February scrimmage between the Union and Orlando City. He has trained plenty, but that's it.

"My rehabilitation has gone well," he said. "I feel like I'm around 90 percent of my normal form."

Curtin will have his say Wednesday, and he might reveal more details then. He'll certainly be asked to.

At least chemistry won't be a problem for Mbaizo. He's been with the organization for three months, and while he isn't fluent in English yet, there are plenty of French speakers in the locker room. One is Eric Ayuk, who played with Mbaizo for Cameroon at last year's Africa Under-20 Cup of Nations.

Mbaizo has gotten a few call-ups to Cameroon's senior national team and played briefly in a game in 2016. Cameroon will host the Africa Cup of Nations in 2019, and Mbaizo said it would be "a dream" to play in the tournament.

He might get an endorsement from a countryman who used to play in MLS: Ambroise Oyongo. Mbaizo is friends with the former New York Red Bulls and Montreal Impact outside back, who now plays for French first-division club Montpellier.

"He's like my big brother," Mbaizo said. "When I told him I was coming here, he was very encouraging. He told me that Philadelphia is a good team."

Time will tell if Mbaizo is able to prove Oyongo right.