Phil Jones told ESPN that a club like Manchester United should be winning the league plus another trophy to make the season a success. (2:45)

Jose Mourinho says injury has cost Sergio Romero the chance to start the FA Cup final for Manchester United, with David De Gea set to feature in goal.

Argentina's No. 1, who started the first four games of United's FA Cup campaign, suffered an injury on international duty in March before making his comeback in the 1-0 win over Watford on the final day of the Premier League season.

But Mourinho says the 31-year-old's return has come too late and De Gea will play against Chelsea at Wembley on Saturday.

"He was injured for a long long time," Mourinho told a news conference on Friday. "He was injured for two and something months. He didn't play some matches that normally would be his matches -- the semifinal against Tottenham, a couple of more matches before the final.

"He trained only one week before the Watford match and a little bit more before and that's the reason."

Romero has by and large been United's cup goalkeeper this season, starting three games in the Carabao Cup and four FA Cup ties.

He was in line to start the FA Cup semifinal against Tottenham last month but missed out after suffering an injury during Argentina's 6-1 defeat to Spain.

Mourinho picked Romero to start last season's Europa League final and the United manager insisted his decision to keep him on the bench against Chelsea was based solely on a lack of fitness.

"It's not about trust, it's not about confidence in him," he added. "We could have felt last season the Europa League final was a much more important match than this one because Europa League final was giving us the possibility to play Champions League and that is first objective of any top-six club -- to finish top four.

"But because we didn't, it was to win the Europa League final and I played Europa League final with Sergio.

"So it's not about confidence or no confidence, it's about process of last couple of months since he had an important injury against Spain."

The FA Cup final offers Mourinho the chance to end a second-successive campaign with at least one trophy after lifting the EFL Cup and the Europa League last season.

Antonio Conte has the same opportunity after Chelsea won the Premier League title 12 months ago but there is still mounting speculation the Italian is set to be sacked this summer.

Chelsea were heavily criticised for their performance during the 3-0 defeat to Newcastle last weekend but Mourinho insists question marks over Conte's position will have no impact on Saturday.

David De Gea will start the FA Cup final for Manchester United ahead of an unfit Sergio Romero. David Price/Arsenal FC via Getty Images

"Honestly, I still don't know what Antonio's situation is," he said. "I still don't know because I didn't read or listen to him saying he is leaving and for me that is the most important thing, Antonio and the club.

"I have no information from Antonio or Chelsea in some official statement that Antonio is leaving, that it's Antonio's last match and for me that is the most important thing.

"Of course sometimes I read, I get people that read and listen, and what you write and what you say is Antonio is leaving, it is Antonio's last match, somebody is leaving, the other one is coming, Luis Enrique is coming, the other one is coming, but until it's official that Antonio leaves I don't know.

"Honestly, you ask me if I'm interested in it -- I'm just curious about it.

"In relation to the match, if it is his last match or if it isn't his last match, I don't think it will change at all his approach to the game and his desire to make it through and his desire to win."

Victory, and a 13th final success for Mourinho, would also be a 13th FA Cup for United.

"I like to play the matches,'' he added. "That's how you should approach finals, you shouldn't go to finals less than very happy. That's the point.

"If you give me the choice of finish the [last] match against Watford and go on holiday, or be working one more week to play a beautiful final, of course I want to play the beautiful final, and I'm sorry I don't have one more week to work until the Champions League final.

"Everybody wants to play finals. You have to be happy. Not nervous. Anxiety is normal but you have to go with happiness.''

Some pundits have expressed fears the showpiece could be a dull, cagey affair, especially given some of United's less-than-cavalier performances this season.

But Mourinho countered: "I don't understand these words of entertaining. Do you think 6-0 is entertaining? I don't think so.

"I think entertaining is emotional until the end, an open result until the end, everybody on their seats until the end, both dugouts nervous and tense with the unpredictability of the result.

"For me as a football lover, not as a manager, that's entertaining. I think it will be entertaining.''

Information from Press Association Sport was used in this story.