NEW YORK -- If the Mets turn to Kodai Senga in relief on Friday, they won¡¯t know exactly what to expect. But it¡¯s entirely possible he will be part of the proceedings.

Senga, who was once in play to start National League Championship Series Game 5 despite his issues in Game 1 on Sunday, is now a candidate to come out of the bullpen for the first time as a Major Leaguer. The Mets chose to start David Peterson in a must-win Game 5 over Senga after managing to avoid using the left-hander in relief during Games 3 and 4.

¡°Facing an elimination game, he¡¯s fully rested,¡± manager Carlos Mendoza said of Peterson. ¡°He's been one of our starters, one of our best starters. We just feel like he¡¯s going to give us the best chance.¡±

Although Peterson hasn¡¯t delivered a full starter¡¯s workload since September and is unlikely to do so in a potential elimination game, the Mets have enough well-rested relievers that they would probably only turn to Senga in a lopsided game. If they do, team officials have confidence that Senga can deliver a more competitive outing than he did in NLCS Game 1, when he threw 20 of his 30 pitches outside the strike zone, walked four batters and threw a wild pitch.

Senga threw a bullpen session Wednesday and looked significantly improved, according to a team decision-maker, which should bolster the Mets¡¯ confidence in him. He also stretched out in the bullpen following his NLCS Game 1 start, which means an effective Senga could throw as many as four innings and approximately 60 pitches out of the bullpen in Game 5.

¡°He¡¯s an ace, man,¡± Mendoza said earlier this week. ¡°This is a guy that we saw making a start against the Braves [in July], and he was lights-out. He pitched against the Phillies [in the NLDS], and he was throwing 96, 97. It was one pitch that [Kyle] Schwarber got him, but other than that, he was pretty good. And then we¡¯re reacting off one outing that he didn¡¯t have it. So I¡¯m pretty confident in giving him the ball.¡±

(While Tylor Megill was also once an option to start Game 5, his three-inning appearance in Game 3's 8-0 loss on Wednesday took him out of play for a bulk assignment Friday.)

Senga was the Mets¡¯ best pitcher last season, producing a 2.98 ERA over 29 starts. And he was effective in two of his three outings this season, including a July 26 start against the Braves and an NLDS Game 1 start against the Phillies. Only in NLCS Game 1 did Senga struggle, explaining afterward that his mechanics were out of whack.

¡°He knows himself better than anybody,¡± Mendoza said. ¡°At times, if something¡¯s off, you¡¯re going to see games like that. But if he¡¯s right, he can be lights-out.¡±

Although one bullpen session represents a microscopic sample size, the Mets don¡¯t have many other data points to evaluate Senga, who missed nearly the entire regular season due to shoulder, triceps and calf injuries. It wasn¡¯t until early October that Mets officials began seriously considering Senga as an option for their playoff roster.

A week and a half into that experiment, they¡¯re no more certain of what Senga can provide them. Peterson represents a lower-variance option, which is a significant reason why he¡¯s starting Game 5.

¡°It means a lot,¡± Peterson said. ¡°Being able to get the ball in a situation like this, and having the confidence of Mendy and the coaching staff is huge.¡±

Senga threw a bullpen session Wednesday and looked significantly improved, according to a team decision-maker, which should bolster the Mets¡¯ confidence in him. He also stretched out in the bullpen following his NLCS Game 1 start, which means an effective Senga could throw as many as four innings and 60-ish pitches in Game 5.

¡°He knows himself better than anybody,¡± Mendoza said. ¡°At times, if something¡¯s off, you¡¯re going to see games like that. But if he¡¯s right, he can be lights-out.¡±

Although one bullpen session represents a microscopic sample size, the Mets don¡¯t have many other data points to evaluate Senga, who missed nearly the entire regular season due to shoulder, triceps and calf injuries. It wasn¡¯t until early October that Mets officials began seriously considering Senga as an option for their playoff roster.

A week and a half into that experiment, they may be no more certain of what Senga can provide them, but they¡¯re still committed to chasing his upside.

¡°I never thought that he was going to be a player for us,¡± Mendoza said. ¡°Now, because of where we¡¯re at, you¡¯re going to need somebody to start the game. He¡¯s an ace. ¡­ That¡¯s why there¡¯s a chance he starts in Game 5.¡±