Another week, another top Bay FC player who didn’t finish the match.

Bay FC surrendered a second-half goal while striker Asisat Oshoala was being evaluated, and that tally gave Bay FC a fourth loss, this one a 2-1 defeat to the Wave in San Diego.

Oshoala, who scored earlier in the match, went down with a non-contact leg injury and was holding her right leg before waving medical staff onto the field. She was on the sideline with the team considering her re-entry while the Wave (2-2-1) weaved through the Bay FC defense and Jaedyn Shaw scored the winner. 

Oshoala didn’t return, a week after Bay FC (2-4-0) lost defensive midfielder Alex Loera to a torn ACL in a 5-2 loss at Kansas City. After the game, Oshoala said, “I’m good,” and head coach Albertin Montoya said it was a cramp.

“Asisat and I were having a conversation if she was going to go back in,” Montoya said. “She felt like she could give us some more minutes, then after the goal happened we decided to make the change. It’s unfortunate, we could have made a substitution at the time, but she was ready to get back in the game and she’s still a huge presence for us up top, so I didn’t want to necessarily take her out at that time. But it’s unfortunate that it all came when they scored a goal.”

Earlier in the match, San Diego struck in the 13th minute after Makenzy Doniak beat Emily Menges and sailed a ball well over the range of goalkeeper  Lysianne Proulx for a 1-0 Wave lead.

Oshoala buried a secondary chance in the 48th minute to equalize it at 1-1. She took a rebound off San Diego’s Kailen Sheridan and went high corner for her second goal of the season.

The Nigerian striker had seemed half a step slow in the opening half, just missing on some passes and firing wide on one late first-half chance. But she was in position to snap her four-match scoreless streak on the tying goal.

While Oshoala was off the field, the Wave tic-tac-toed around Menges and Savy King in the 78th minute, leading to a tally for Shaw. Oshoala was on the sideline and Bay FC hadn’t yet subbed for her, leading to 10 players against San Diego’s 11 during the Wave’s go-ahead goal.

“The second goal was my fault,” Menges said. “We’ve made huge strides as a team defensively.”

“The second goal was just a good combination play,” Oshoala added. “Everyone became better today; we’re not going to point fingers at anyone.  We win together and take blame as a team together.”

The Wave’s five goals allowed are the second fewest in the NWSL this season, and the fewest of teams that have played six games. Bay FC generated 22 shots, but just three were on goal even with 15 coming from inside the box.

“I don’t know if this is the most frustrating (loss), because we’ve let in a lot of goals late in games,” Montoya said. “It hurts because I think the team deserved better. They played well, but there are little things we need to continue to improve on.”

Scarlett Camberos returned to the lineup after missing two games with a leg injury and she started alongside Oshoala and Racheal Kundananji. That relocated Tess Boade to the midfield after she had started every match at the right forward spot.

Boade was at midfield in place of Loera, who is out for the season with an ACL tear. Boade and Dorian Bailey worked together as a double pivot in the No. 6 spot as the conduit into the offensive side of the ball, where Loera had handled that transition in previous games. Deyna Castellanos, who has started every Bay FC match at offensive midfielder, stayed in the same spot as Bay FC stuck with the 4-3-3.

“It’s difficult to replace a player like Alex,” Montoya said. “Moving forward, we may look at playing with the double six depending on the team and then depending on whether we continue to improve defensively. But it gives us a better balance and something new to see how it works.”

Saturday’s match was the first of three for Bay FC in an eight-day stretch. The team will host Portland on Wednesday night and then Chicago next Sunday. Some decisions, such as Caprice Dydasco’s early sub off, came with that in mind against the Wave.

Reach Marisa Ingemi: marisa.ingemi@sfchronicle.com; Twitter: @marisa_ingemi