Ryan Giggs has admitted that Louis van Gaal, the favourite to become Manchester United's new manager, has a "fantastic pedigree" after winning the league in three different countries and that his own future may lie away from Old Trafford.

Giggs, who takes charge of a second match as interim manager for Saturday's visit of Sunderland, is aware that Van Gaal has been a success when managing Ajax and AZ Alkmaar in his homeland, Barcelona in Spain, and with Bayern Munich in Germany. The 62-year-old has claimed championships with all four clubs, plus the Champions League and Uefa Cup when at Ajax.

Talking about Van Gaal's abilities for the first time since the Dutchman was linked with United, Giggs said: "He's got a brilliant reputation and is a successful manager in different countries. He's taken Holland to the World Cup. Yes, he's got fantastic pedigree."

Giggs has so far impressed in the caretaker role, leading United to last Saturday's 4-0 win over Norwich City at Old Trafford. While it is understood the Welshman would like to be considered for the permanent position his chances remain remote, with the club's hierarchy targeting Van Gaal.

Giggs hinted he would consider leaving United to become a manager of another club "somewhere else", though the Welshman insisted any decision over his future will be at the end of the campaign.

Asked if he would want to be No2 to Van Gaal or any new manager, the 40-year-old said: "I have got to decide if I want to play or not so there is no point thinking if I want to be an assistant or if I want to be a manager somewhere else.

"There are so many things to think about. The way I am thinking is I am enjoying it and then my concentration is on the remaining two games and then, like I have just said, we will see what happens at the end of the season."

Giggs insisted he is just getting on with being the interim manager, having spent the week discussing youth player contracts and the club's summer tour.

"Nothing has changed. We'll chat when the season's over," he said. "I've got a lot to think about, whether to carry on playing. But my concentration is just on managing United now. The only peace and quiet you do get is when you are on the training pitch. As soon as you're back in the office, you have meetings, you have calls.

"For example this week has been planning pre-season, which has been testing because we have to wait and see about the Europa League and the qualifying round three, for that is around about the tour time, so there are different permutations. Also, it is a difficult time for young players, extending and renewing contracts, loan players, players that need to come back, players that need their futures sorting out, so there has been a lot of that this week."

Wayne Rooney is a doubt to face Sunderland as he has a stomach bug and "tight groin", with the other players in the United camp, including the goalkeeper, Anders Lindegaard, also suffering from the digestive complaint.

Giggs said: "A few of the lads have had a bug. Anders and Wayne have both had a bug. Wayne's also got a tight groin. And obviously with a bug you have to be careful with that because of the immune system being down a bit. Wayne being Wayne, he wants to play and be involved so we'll just monitor him over the next 24 hours."

Robin van Persie, who has not played since 19 March due to a knee injury, could again be in contention. "Robin's looked good in training. Whether it is too early, we'll just see how he goes," said Giggs.

Rio Ferdinand and Patrice Evra, each of whom have contracts that expire at the close of the term, could leave. Yet their interim manager believes both have a future at the 20-times champions. "I'd like them to stay on. It's their decision, their contracts are both up," said Giggs. "They have both given massive service to the club and they are both fit, and looked good last week. I don't see why not."

Whose call would that be? "It's everyone's decision – it's Rio's, it's Pat's and it's Ed's [Woodward, the executive vice-chairman] and whoever is the manager next year," he said. "I think it is a group discussion but I still think they have got a lot to offer. They've been great players and remain assets to a club like Manchester United."

After Sunderland's visit, Hull City are the opponents in midweek for United's final home match this season. Has Giggs considered he might have made his last appearance at Old Trafford?

"Again, it's not something I've thought about. We'll just have to wait and see. I'll have to see how the team performs and see if I can get in," he joked. "My main priority is winning the games. Is me playing giving us the best chance? We'll see."

While Woodward has stated there could be an unprecedented investment in the squad this summer, Giggs believes there remain many good players at United.

"What I do want to see is plenty of quality at the club," he said. "Whether you have won a Premier League and been successful or you've not been successful, like this year, you always look to strengthen. That will never change. If the players are out there you try to get them. If there are players who can improve you and take you forward then you try to get them."

Giggs was asked whether he thought this would be the club's most important close season since he joined. "No, I think every summer is important. After the treble-winning season in 1999 you ask: 'Where do you go from there?' The answer is you try to improve," he said. "It's always important whether it's been a successful season or not. It's not been a great season this year. It's important we get the right players in and improve on this season."